English Medium Class 10 - CBSE Question Bank Solutions for Science

A cylindrical structure P in our body begins in continuation with medulla and extends downwards. It is enclosed in a bony cage Q and surrounded by membranes R. As many as x pairs of nerves arise from the structure P. The structure P is involved in the reflex actions of our body and conduction of nerve impulses to and from another organ S of our body with which it forms CNS.
(a) Name the structure P.
(b) Name (i) bony cage Q, and (ii) membranes R.
(c) How much is x?
(d) Name the organs S.
(e) What are the reflexes involving structure P only known as?

Write down the following activities in the correct order for a simple reflex arc:
(a) impulse travels in the motor fibre
(b) impulse travels in the sensory fibre
(c) effector organ stimulated
(d) impulse crosses the synapse

A solid substance P which is very hard is used in the construction of many buildings, especially flooring. When substance P is heated strongly, it decomposes to form another solid Q and a gas R is given out. Solid Q reacts with water with the release of a lot of heat to form a substance S. When gas R is passed into a clear solution of substance S, then a white precipitate of substance T is formed. The substance T has the same chemical composition as starting substance P.
(a) What is substance P? Write its common name as well as chemical formula.
(b) What is substance Q?
(c) What is gas R?
(d) What is substance S? What is its clear solution known as?
(e) What is substance T? Name any two natural forms in which substance T occurs in nature.

The white solid compound A decomposes quite rapidly on heating in the presence of a black substance X to form a solid compound B and a gas C. When an aqueous solution of compound B is reacted with silver nitrate solution, then a white precipitate of silver chloride is obtained along with potassium nitrate solution. Gas C does not burn itself but helps burn other things.
(a) What is compound A?
(b) What is compound B?
(c) What is gas C?
(d) What do you think is the black substance X? What is its function?
(e) What is the general name of substances like X?

What type of reaction is represented by the digestion of food in our body?

State an important use of decomposition reactions.

Give one example of a decomposition reaction which is carried out by applying heat.

Give one example of a decomposition reaction which is carried out with electricity.

What type of chemical reaction is used to extract metals from their naturally occurring compounds like oxides or chlorides?

What type of reaction is represented by the following equation?

\[\ce{CaCO3 -> CaCO + CO2}\]

What type of reaction is represented by the following equation?

2 FeSO₄ → Fe₂ O₃ + SO₂ + SO₃

What type of reaction is represented by the following equation?

NH₄ CI → NH₃  +  HCI

What type of chemical reaction take place when lime-stone is heated?

What type of chemical reaction take place when silver bromide is exposed to sunlight?

What type of chemical reaction take place when electricity is passed through water?

What type of chemical reaction is represented by the following equation?

X → Y + Z

What type of reaction is represented by the following equation?

NH₄NO₂ → N₂ + 2H₂O

What is the colour of ferrous sulphate crystals? How does this colour change after heating?

Name the product formed on strongly heating ferrous sulphate crystals. What type of chemical reaction occurs in this change?

What is a decomposition reaction?