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Showing posts with label X Chemistry. Show all posts

Class 10 Science Cbse Ncert Solutions of Control and Coordination - InText Questions

 

Control and Coordination

Class 10 Science NCERT Solutions of Chapter 7 InText Questions

Control and Coordination - NCERT Solutions of Intext Questions (Page 119)

Question 1: What is the difference between a reflex action and walking?
Answer: Reflex action is a process by which we do something without thinking about it or without being in control of our reactions. It is an automatic response to a stimulus which is done by only the spinal cord without the help of brain.
While walking is a process which is done by thinking, or it is performed by the brain under conscious control unlike reflex action.
Question 2: What happens at the synapse between two neurons?
Answer:  A very small gap that occurs between the last portion of axon of one neuron and the dendron of another neuron is known as synapse. Synapse acts as one way valve to transmit impulses in one direction only. The uni-directional transfer of impulses occur due to the release of some chemicals in only one side of the neuron, ie, the axon's side. These chemicals cross the synapse and start a simple impulse in the dendrite of next neuron.
Question 3: Which part of the brain maintains posture and equilibrium of the body?
Answer: Cerebellum, a part of hind brain is responsible for maintaining the posture and equilibrium of the body.
Question 4: How do we detect the smell of an agarbatti (incense sick)?
Answer:  The smell of an agarbatti is detected by the forebrain. There are separate areas in our forebrain which are specialised for hearing, smelling, sight, taste, touch etc. Our forebrain has also regions that collect information or impulses from the various receptors. When the smell of an agarbatti reaches us, our forebrain interprets it by putting it together with the information received from other receptors and also with the information already stored in the brain.
Question 5: What is the role of the brain in reflex action?
Answer:  Reflex actions are sudden responses to a change in the environment which we do without thinking about it. The nerves from all over the body meet in a bundle in the spinal cord. Thus, reflex arcs are formed in the spinal cord and the information input also goes on to reach the brain. In reflex arc instant and automatic responses possible. The brain is only aware of the signal and the response that has taken place. Here, the brain has no role to play in the creation of the response done by reflex action.

Control and Coordination - NCERT Answers of Intext Questions (Page 122)

Question 1: What are plant hormones?
Answer:  Plant hormones are the chemicals released by stimulated cells. This chemical compounds help to coordinate growth, development and responses to the environment. These are synthesised at places away from where they act. The five different types of plant hormones (phytohormones) are Auxins, Gibberellins, Cytokinins, Abscisic acid, and Ethylene.
Question 2: How is the movement of leaves of the sensitive plant different from the movement of a shoot towards light?
Answer: The movement of leaves of the sensitive plant like Mimosa pudica or "touch-me-not" is either towards nor away from stimulus like touch. While movement of shoot is towards stimulus like light. The movement of leaves of sensitive plants is not directional while the movement of shoot is directional.
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Question 3: Give an example of a plant hormone that promotes growth.
Answer: (i) Auxins help to increase the length of plants.
(ii) Gibberellins help in the growth of stem.
Question 4: How do Auxins promote the growth of a tendril around a support?
Answer: Auxin is synthesised at the shoot tip. The tendrils are sensitive to touch. As these tendrils come in the contact with the support, the auxin diffuses towards the other side away from the support. As it stimulates faster growth of the cells, so, this part grows more rapidly than the other. This causes the tendril to circle around the support and thus climb upwards.
Question 5: Design an experiment to demonstrate hydrotropism.
Answer: Positive hydrotropism can be demonstrated with germinated seedlings, which are allowed to grow on ground (Fig. 7.2). The soil below the roots is separated by a polythene partition. The left side is kept moist but the right side is kept dry. The radicals at first grow in a downward direction due to the effect of gravity (positive geotropism), but after sometime, the roots bend toward the moist soil (positive hydrotropism). This is evidently due to the closeness of the germinating roots to water.

Control and Coordination - NCERT Solutions of Intext Questions (Page 125)

Question 1: How does chemical coordination take place in animals?
Answer: Chemical coordination takes place in animals with the help of some chemical substances called hormones. Hormones are secreted by endocrine glands. The timing and amount of hormone released are regulated by feedback mechanisms.
Question 2: Why is the use of iodised salt advisable?
Answer: The use of iodised salt is advisable because iodine is necessary for the thyroid gland to produce thyroxine hormone. Thyroxine relates carbohydrates, protein and fat metabolism in the body so as to provide the best balance for growth. Iodine is essential for the synthesis of thyroxine. Deficiency of this hormone results in the enlargement of the thyroid gland. This can lead to goitre. Therefore, iodised salt is advised for normal functioning of the thyroid gland.
Question 3: How does our body respond when adrenaline is secreted into the blood?
Answer: Adrenaline is a hormone secreted by the adrenal glands in case of any danger, emergency or any kinds of stress. It is secreted directly into the blood and is carried to different parts of the body. It acts on heart also. As a result, the heart beats faster in order to supply more oxygen to the muscles. This also increases the blood pressure. All these responses enable our body to deal with the situation.
Question 4: Why are some patients of diabetes treated by injections of insulin?
Answer: Insulin is a hormone which is produced by the pancreas and helps in regulating blood sugar levels. If insulin is not secreted in proper amounts, the sugar level in the blood increases causing diabetes which has many harmful effects. Therefore, the patients of diabetes are treated by giving injections of insulin.
 Class 10 NCERT Science Chapter 7, Control and Coordination - Related Posts

Metals and Non-Metals - NCERT Answers of Class 10 NCERT Science Chapter 3 exercise questions

 

Metals and Non-Metals

Class 10 NCERT Solutions for Science Chapter 3 Textbook Exercise Questions

Question 1: Which of the following pairs will give displacement reactions?
(a) NaCl solution and copper metal.
(b) MgCl2 solution and aluminium metal.
(c) FeSO4 solution and silver metal.
(d) AgNO3 solution and copper metal.
Answer: (d)

Question 2: Which of the following methods is suitable for preventing an iron frying pan from rusting?
(a) Applying grease
(b) Applying paint
(c) Applying a coating of zinc
(d) All of the above.
Answer: (c)

Question 3: An element reacts with oxygen to give a compound with a high melting point. This compound is also soluble in water. The element is likely to be
(a) Calcium
(b) Carbon
(c) Silicon
(d) Iron.
Answer: (a)

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Question 4: Food cans are coated with tin and not with zinc because
(a) Zinc is costlier than tin.
(b) Zinc has a higher melting point than tin.
(c) Zinc is more reactive than tin.
(d) Zinc is less reactive than tin.
Answer: (c)

Question 5: You are given a hammer, a battery, a bulb, wires and a switch.
(a) How could you use them to distinguish between samples of metals and non-metals?
(b) Assess the usefulness of these tests in distinguishing between metals and non-metals.
Answer: (a)
CBSE Guide NCERT Solution - image
By beating the samples with hammer we can check its malleability. If the sample is malleable then it is a metal otherwise non-metal. Similarly, we will make a circuit as shown in the figure and check the electrical conductivity of the sample. If with the sample (test material), the bulb glows on turning the switch on, the sample is likely to be a metal otherwise a non-metal.

(b) The above tests are generally useful in distinguishing between metals and non-metals. Since, these are based on only physical properties and no chemical reaction is involved in these tests. Only exception is graphite which is a good conductor of electricity although it is a non-metal.




Question 6: What are amphoteric oxides? Give two examples of amphoteric oxides.
Answer: The metal oxides are basic in nature. But some metal oxides show both acidic and basic behaviour and hence, react with both acids as well as bases to produce salts and water. These oxides are known as Amphoteric Oxides. For example, aluminium oxide reacts in the following manner with acids and bases:
Another example of amphoteric oxide is - Zinc oxide.

Question 7: Name two metals which will displace hydrogen from dilute acids, and two metals which will not.
Answer: Metals that displace hydrogen: Magnesium, zinc. Metals that do not displace hydrogen: Copper, gold.

Question 8: In the electrolytic refining of a metal M, what would you take as the anode, the cathode and the electrolyte?
Answer:
Cbse Ncert Solution - image
In this process, the impure metal is made the anode and a thin strip of pure metal is made the cathode. A solution of the metal salt is used as an electrolyte. The apparatus is set up as shown in the above figure.

Question 9: Pratyush took Sulphur powder on a spatula and heated it. He collected the gas evolved by inverting a test tube over it, as shown in figure below.
https://www.cbsencertsolution.com
(a) What will be the action of gas on
(i) dry litmus paper?
(ii) moist litmus paper?
(b) Write a balanced chemical equation for the reaction taking place.
Answer: (a) (i) No effect on dry litmus paper.
(ii) Turns blue litmus red in moist state. The gas is Sulphur dioxide, which will react with the H2O of moist blue litmus paper and form sulphurous acid (H2SO3). This acid turns blue litmus into red.
(b)
Question 10: State two ways to prevent the rusting of iron.
Answer: Rusting of iron can be prevented by making by it unable to come in contact with moisture and oxygen present in atmosphere. This can be done either by -
1. Galvanisation: A method in which a coating of zinc is made on the iron article.
2. By applying a coating of paint or grease or oil on the iron article.

Question 11: What types of oxides are formed when non-metals combine with oxygen?
Answer: Acidic oxides.

Question 12: Give reasons:
(a) Platinum, gold and silver are used to make jewellery.
(b) Sodium, potassium and lithium are stored under oil.
(c) Aluminium is a highly reactive metal, yet it is used to make utensils for cooking.
(d) Carbonate and sulphide ores are usually converted into oxides during the process of extraction.
Answer:
(a) Platinum, gold and silver are very less reactive and do not corrode. They also possess very brilliant lustre due to which jewelleries made with these metals look beautiful.
(b) Metals such as potassium, sodium and lithium react with air so vigorously that they catch fire if kept in the open. Hence, to protect them and to prevent accidental fires, they are kept immersed in kerosene oil.
(c) In spite of being a highly reactive metal, aluminium does not corrode easily. This is because aluminium reacts with oxygen present in air and forms a thin layer of aluminium oxide. This layer of aluminium oxide is very stable and thus, prevents further reaction of aluminium with oxygen. It is also a very good conductor of heat and light in weight. Because of the above reasons aluminium is used to make utensils for cooking.
(d) It is easier to obtain a metal from its oxide, as compared to its sulphides and carbonates. Therefore, prior to reduction, the metal sulphides and carbonates must be converted into metal oxides.  

Question 13: You must have seen tarnished copper vessels being cleaned with lemon or tamarind juice. Explain why these sour substances are effective in cleaning the vessels.
Answer: It is because the basic oxides of copper like - copper oxide and copper carbonate formed on the copper vessels react with the acid present in the sour substances like lemon and tamarind and get dissolved and removed. Hence, lemon or tamarind and similar sour substances are used to clean copper vessels as they remove the corroded part of copper vessels and pure copper is exposed.

Question 14: Differentiate between metal and non-metal on the basis of their chemical properties.
Answer:
Metal
Non-metal
Metals are positively charged ions (cation).
Non-metals are negatively charged ions (anion).
They react with the oxygen to form basic oxides.
They react with the oxygen to form acidic or neutral oxides.
Metallic oxides have Ionic bonds.
Non-Metallic oxides have Covalent bonds.
Metals also form amphoteric oxides after reacting with oxygen. (Some metal oxides are amphoteric oxides).
Non-metal oxides are not amphoteric oxides.
Metals react with water to form oxides and Hydroxides. Some metals react with cold water, some with hot water while others with steam.
Non-metals do not react with water.
They react with dilute acids to form salt and hydrogen gas. Exceptions: Cu, Ag, Au, Pt, Hg.
Non-metals do not react with dilute acids.
Depending on their reactivity, metals react with the salt solution of other metals. Example: CuSO4 + Zn ----> ZnSO4 + Cu
They react with the salt solution of non-metals.
Metals are generally reducing agents. Since, they can easily loose electrons.
Non-metals are generally oxidising agents. Since, they can easily gain electrons.

Question 15: A man went door to door posing as a goldsmith. He promised to bring back the glitter of old and dull gold ornaments. An unsuspecting lady gave a set of gold bangles to him which he dipped in a particular solution. The bangles sparkled like new but their weight was reduced drastically. The lady was upset but after a futile argument the man beat a hasty retreat. Can you play the detective to find out the nature of the solution he had used?
Answer: The solution which the goldsmith used was aqua regia. It is a highly corrosive liquid and dissolves the gold in it.

Question 16: Give reasons why copper is used to make hot water tanks and not steel (an alloy of iron).
Answer: Copper doesn't react with water. But iron reacts with steam. So, if hot water tanks are made of steel which is an alloy of iron, then its iron content will react with steam formed from hot water. That is why, copper is used to make hot water tanks and steel is not.
 Class 10 NCERT Solutions CBSE Guide - Related Posts

Metals and Non-Metals - Cbse Ncert Solutions of Class 10 Science Chapter 3 InText Questions

 

Metals and Non-metals

Class X, NCERT Solutions of Chapter 3 Science InText Questions


CBSE NCERT Solutions: InText Questions (Page 40)
Question 1: Give an example of a metal which
(i) is a liquid at room temperature.
(ii) can be easily cut with a knife.
(iii) is the best conductor of heat.
(iv) is a poor conductor of heat.
Answer: (i) Mercury.  (ii) Sodium.  (iii) Silver.  (iv) Lead and Mercury.

Question 2: Explain the meanings of malleable and ductile.
Answer:
Malleable: Some metals can be beaten into thin sheets. This property is called malleability and such substances are called malleable. For example gold, silver.
Ductile: Substances that can be drawn into thin wires are called ductile. Most of the metals are ductile.

CBSE NCERT Solutions: InText Questions (Page 46)
Question 3: Why is sodium kept immersed in kerosene oil?
Answer: Sodium is highly reactive on exposure to air at room temperature. It reacts with oxygen and catches fire. It also reacts with water. But, it neither reacts nor dissolves in kerosene. So, in order to protect it sodium is kept under kerosene.

Question 4: Write equations for the reactions of
(i) Iron with steam
(ii) Calcium and potassium with water
Answer:  
https://www.cbsencertsolution.com/2019/02/metals-and-non-metals-cbse-ncert-solutions-of-class-10-science-chapter-3-intext.html
Question 5: Samples of four metals A, B, C and D were taken and added to the following solution one by one. The results obtained have been tabulated as follows:
Metal
Iron (II) sulphate
Copper (II) sulphate
Zinc sulphate
Silver nitrate
A
No reaction
Displacement


B
Displacement

No reaction

C
No reaction
No reaction
No reaction
Displacement
D
No reaction
No reaction
No reaction
No reaction

Use the Table above to answer the following questions about metals A, B, C and D.
(i) Which is the most reactive metal?
(ii) What would you observe if B is added to a solution of Copper (II) sulphate?
(iii) Arrange the metals A, B, C and D in the order of decreasing reactivity.
Answer:  From the above table we obtain the reactivity series as follows:
Zn > B > Fe > A > Cu > C > Ag > D
(i) Metal B is the most reactive metal.
(ii) Displacement reaction.
(iii) Metal B > Metal A > Metal C > Metal D.

Question 6: Which gas is produced when dilute hydrochloric acid is added to a reactive metal? Write the chemical reaction when iron reacts with dilute H2SO4.
Answer: Hydrogen gas is evolved along with salt of the metal. Equation for the chemical reaction that will take place between iron and dil. H2SO4 is -
https://www.cbsencertsolution.com/2019/02/metals-and-non-metals-cbse-ncert-solutions-of-class-10-science-chapter-3-intext.html



Question 7: What would you observe when zinc is added to a solution of iron(II) sulphate? Write the chemical reaction that takes place.
Answer:  Since, zinc is more reactive than iron. So, it will displace iron from iron(II) sulphate. The equation will be as follows:
https://www.cbsencertsolution.com/2019/02/metals-and-non-metals-cbse-ncert-solutions-of-class-10-science-chapter-3-intext.html



CBSE NCERT Solutions: InText Questions (Page 49)
Question 8: (i) Write the electron-dot structures for sodium, oxygen and magnesium.
(ii) Show the formation of Na2O and MgO by transfer of electrons.
(iii) What are the ions present in these compounds?
Answer: (i)
https://www.cbsencertsolution.com












(ii)
https://www.cbsencertsolution.com/2019/02/metals-and-non-metals-cbse-ncert-solutions-of-class-10-science-chapter-3-intext.html













(iii)
https://www.cbsencertsolution.com/2019/02/metals-and-non-metals-cbse-ncert-solutions-of-class-10-science-chapter-3-intext.html




 Question 9: Why do Ionic compounds have high melting points?
Answer: The molecules of Ionic compounds are bounded by strong electrostatic force of attraction between the ions. Hence, it requires a lot of energy to overcome these forces and so Ionic compounds have high melting and boiling points.

CBSE NCERT Solutions: InText Questions (Page 53)



 Question 10: Define the following terms.
(i) Mineral (ii) Ore (iii) Gangue
Answer: (i) Mineral - The elements or compounds which occur naturally in the earth's crust are known as minerals.
(ii) Ore - At some places, minerals contain a very high percentage of a particular metal and the metal can be profitably extracted from it. These minerals are called ores.
(iii) Gangue - Ores mined from the earth are usually contaminated with large amounts of impurities such as soil, sand, etc, called gangue.

Question 11: Name two metals which are found in nature in the free state.
Answer: Gold, Platinum.

Question 12: What chemical process is used for obtaining a metal from its oxide?
Answer: The chemical process used for obtaining a metal from its oxide is reduction. The metal oxides are reduced by using a suitable reducing agent like carbon or by a more reactive metal to cause a displacement reaction. For example,




CBSE NCERT Solutions: InText Questions (Page 55)
Question 13: Metallic oxides of zinc, magnesium and copper were heated with the following metals.
Metal
Zinc
Magnesium
Copper
Zinc oxide



Magnesium oxide



Copper oxide




In which cases will you find displacement reactions taking place?
Answer:
Metal
Zinc
Magnesium
Copper
Zinc oxide
No
Yes
No
Magnesium oxide
No
No
No
Copper oxide
Yes
Yes
No

Question 14: Which metals do not corrode easily?
Answer: More reactive a metal, the chances of its corrosion is more. So, metals low in activity series, like gold, silver, etc. do not corrode easily.

Question 15: What are alloys?
Answer: An alloy is a homogenous mixture of two or more metals, or a metal and a non-metal.

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