Identify the wrong statements and correct them.

i) Sodium benzoate is used in food preservative.

ii) Nitric acid is not used as fertilizer in agriculture.

iii) Sulphuric acid is called the king of chemicals.

iv) The PH of acid is greater than 7.

v) Acetic acid is used in aerated drinks.

Observe the given chemical change and answer the following:

i) Identify ‘A’ and ‘B’.

ii) Write the commercial name of calcium hydroxide.

iii) Identify products ‘C’ and 'D' , when HCl is allowed to react with calcium oxide.

iv) Say whether calcium oxide is acidic or basic.

Take copper nitrate in a test tube and heat it over the flame.

i) What is the colour of cupric nitrate?

ii) What do you observe?

iii) Name the type of reaction that takes place.

iv) Write the balanced equation.

Redox reactions are reactions during which electron transfer takes place. Here

magnesium atom transfers two electrons one each to the two chlorine atoms.

i) What are the products of this reaction?

ii) Write the balanced equation for the complete reaction.

iii) Which element is being oxidized?

iv) Which element is being reduced?

v) Write the reduction part of the reaction.

Suggest a reason for each observation given below.

i) In fireworks, powdered magnesium is used rather than magnesium ribbon.

ii) Zinc and dilute H₂SO₄ react much more quickly when a few drops of copper sulphate solutions are added.

iii) The reaction between magnesium carbonate and dilute hydrochloric acid speeds

up when some concentrated HCl is added.