English Medium कक्षा १० - CBSE Question Bank Solutions

What do you understand by exothermic reactions?

What do you understand by endothermic reactions?

Give one example of an exothermic reaction.

Give one example  of an endothermic reaction.

Is Burning of natural gas an endothermic reaction or an exothermic reaction?

Is Photosynthesis an endothermic reaction or an exothermic reaction?

Is Electrolysis of water an endothermic reaction or an exothermic reaction?

Is Respiration an endothermic reaction or an exothermic reaction?

Is Decomposition of calcium carbonate an endothermic reaction or an exothermic reaction?

One of the following does not happen during a chemical reaction. This is:
(a) Breaking of old chemical bonds and formation of new chemical bonds
(b) Formation of new substances with entirely different properties
(c) Atoms of one element change into those of another element to form new products.
(d) A rearrangement of atoms takes place to form new products.

Which of the following does not involve a chemical reaction?

You are given the solution of lead nitrate. In order to obtain a yellow precipitate you should mix with it a solution of:
(a) potassium chloride
(b) potassium nitride
(c) potassium sulphide
(d) potassium iodide

An acid which can decolourise purple coloured potassium permanganate solution is:
(a) sulphuric acid
(b) citric acid
(c) carbonic acid
(d) hydrochloric acid

The chemical reaction between two substances is characterised by a change in colour from orange to green. These two substances are most likely to be:
(a) potassium dichromate solution and sulphur dioxide
(b) potassium permanganate solution and sulphur dioxide
(c) potassium permanganate solution  and lemon juice
(d) potassium dichromate solution and carbon dioxide.

The chemical reaction between quicklime and water is characterised by:
(a) evolution of hydrogen gas
(b) formation of slaked lime precipitate
(c) change in temperature of mixture
(d) change in colour of the product

Which of the following is not an endothermic reaction?

(a) CaCO₃ → CaO  +  CO₂

(b) 2H₂O →2H₂ + O₂

(c) 6CO₂ + 6H₂O → C₆H₁₂O₆  +  6O₂

(d) C₆H₁₂O₆  + 6O₂ → 6CO₂  + 6H₂O

One of the following is an exothermic reaction. This is:
(a) electrolysis of water
(b) conversion of limestone into quicklime
(c) process of respiration
(d) process of photosynthesis

The chemical equations are balanced to satisfy one of the following laws in chemical reactions. This law is know as:
(a) law of conservation of momentum
(b) law of conservation of mass
(c) law of conservation of motion
(d) law of conservation of magnetism

When the solution of substance X is added to a solution of potassium iodide, then a yellow solid separates out from the solution.
(a) What do you think substance X is likely to be?
(b) Name the substance which the yellow solid consists of.
(c) Which characteristic of chemical reaction is illustrated by this example?
(d) Write a balanced chemical equation for the reaction which takes place. Mention the physical states of all the reactant and products involved in the chemical equation.

When water is added gradually to a white solid X, a hissing sound is heard and a lot of heat is produced forming a product Y. A suspension of Y in water is applied to the walls of a house during white washing. A clear solution of Y is also used for testing carbon dioxide gas in the laboratory.
(a) What could be solid X? Write its chemical formula.
(b) What could be product Y? Write its chemical formula.
(c) What is the common name of the solution of Y which is used for testing carbon dioxide gas?
(d) Write chemical equation of the reaction which takes place on adding water to slid X.
(e) Which characteristic of chemical reactions is illustrated by this example?