Assertion (A): There is a need to balance a chemical equation.

Reason (R): Matter can neither be created nor be destroyed, it can only be converted from one form to another.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Assertion (A): When a few drops of an aqueous solution of silver nitrate are added to the aqueous solution of sodium chloride, a white precipitate of silver chloride is formed.

Reason (R): Some substances react only when they are heated together.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Fill in the blanks:

(a) The substances which undergo chemical change are called …………… .

(b) The substances formed as a result of a chemical reaction are called …………… .

(c) During a chemical reaction, transfer of …………… takes place.

(d) The basic condition necessary for a chemical reaction is …………… .

(e) In some chemical reactions, an insoluble …………… is formed when two solutions are mixed.

Write True or False for the following statements:

(a) No new substance is formed during a chemical reaction.

(b) Hydrogen sulphide has rotten egg smell.

(c) When potassium iodide solution is added to lead acetate solution, a red precipitate is formed.

(d) A black residue is formed when sugar is heated.

(e) When iron and sulphur are heated together a grey mass is formed which is attracted by a magnet.