Which of the statements about the reaction below are incorrect?
2PbO(s) + C(s) \(\rightarrow\) 2Pb(s) + CO₂(g)
(a) Lead is getting reduced      
(b) Carbon dioxide is getting oxidized
(c) Carbon is getting oxidized    
(d) Lead oxide is getting reduced.

Which of the following statements about the given reaction are correct?
3Fe(s) + 4H₂O(g) \(\rightarrow\) Fe₃O₄(s) + 4H₂(g)
(i) Iron metal is getting oxidised
(ii) Water is getting reduced
(iii) Water is acting as reducing agent
(iv) Water is acting as oxidising agent

Three beakers labelled as A, B and C each containing 25 mL of water was taken. A small amount of NaOH, anhydrous CuSO₄ and NaCl were added to the beakers A, B and C respectively. It was observed that there was an increase in the temperature of the solutions contained in beakers A and B, whereas in case of beaker C, the temperature of the solution falls. Which one of the following statement(s) is (are) correct?
(i) In beakers A and B, exothermic process has occurred.
(ii) In beakers A and B, endothermic process has occurred.
(iii) In beaker C exothermic process has occurred.
(iv) In beaker C endothermic process has occured.

Solid calcium oxide reacts vigorously with water to form calcium hydroxide accompanied by liberation of heat. This process is called slaking of lime. Calcium hydroxide dissolves in water to form its solution called lime water. Which among the following is (are) true about slaking of lime and the solution formed?
(i) It is an endothermic reaction
(ii) It is an exothermic reaction
(iii) The pH of the resulting solution will be more than seven
((iv) The pH of the resulting solution will be less than seven

Chemically rust is

Why does magnesium powder react much more rapidly than magnesium ribbon with dilute sulphuric acid?

Name the reaction which forms insoluble salts.

State one basic difference between a physical change and a chemical change.

Write the chemical equation for reactions that takes place when lead nitrate and potassium iodide solutions are mixed.

A solution of a substance 'X' is used for white washing.
(i) Name the substance 'X' and write its formula.
(ii) Write the reaction of the substance 'X' named in (i) above with water.

Translate the following statements into chemical equations and then balance them.
(a) Hydrogen gas combines with nitrogen to form ammonia
(b) Hydrogen sulphide gas burns in air to give water and sulphur dioxide
(c) Barium chloride reacts with aluminium sulphate to give aluminium chloride and a precipitate of barium sulphate
(d) Potassium metal reacts with water to give potassium hydroxide and hydrogen gas.

Why do we apply paint on iron articles?

Explain and name the type of reaction seen when iron reacts with hydrochloric acid.

Balance the following chemical equation:
MnO₂ + HCl \(\rightarrow\) MnCl₂ + Cl₂ + H₂O

(a) Mention the four informations given by an equation.
(b) State the law of conservation of mass as applicable in a chemical reaction.

2g ferrous sulphate crystals are heated in a dry boiling tube.
(i) List any two observations.
(ii) Name the type of chemical reaction taking place.
(iii) Write the chemical equation of the reaction.

Identify the type of each of the following reactions. Also write balanced chemical equation for each.
(i) The reaction mixture becomes warm.
(ii) An insoluble substance is formed.

Complete and balance the following chemical equations:
(i) CaCO₃ + HCl
(ii) Al + HCl
(iii) MnO₂ + HCI

Give the characteristic tests for the following gases:
(a) CO₂
(b) SO₂
(c) O₂
(d) H₂

What happens when zinc granules are treated with dilute solution of H₂SO₄, HCl, HNO₃, NaCl and NaOH, also write the chemical equations if reaction occurs.

On adding a drop of barium chloride solution to an aqueous solution of sodium sulphite, white precipitate is obtained.
(a) Write a balanced chemical equation of the reaction involved.
(b) What other name can be given to this precipitation reaction?
(c) On adding dilute hydrochloric acid to the reaction mixture, white precipitate disappears. Why?