CBSE - Chemical Reactions and Equations

1 Chemical Reactions and Equations 

The addition of oxygen to a substance is called

(1) Redox
(2) Oxidation
(3) Reduction
(4) None of these

2 Chemical Reactions and Equations 

Which of the following is not a redox reaction?

(1)  2Mg + O₂ --> 2MgO
(2) CaCO₃  + 2HCl  --> CaCl₂ + CO₂ +  H₂O
(3) 2CuCl₂  --> Cu₂Cl₂  + Cl₂
(4) SO₂  + I₂  + 2H₂O--> H₂SO₄ + 2HI

3 Chemical Reactions and Equations 

When a student put some copper turnings in a colourless solution, he observed that the solution gradually turned blue. The solution is most likely to be

(1) Ferrous sulphate solution
(2) Magnesium nitrate solution
(3) Silver nitrate solution
(4) Copper sulphate solution

4 Chemical Reactions and Equations 

Which of the following pair of reactants can undergo displacement reaction under appropriate conditions ? 

(1) MgSO₄ + Fe 
(2) ZnSO₄ + Fe 
(3) MgSO₄ + Pb 
(4) CuSO₄ + Fe

5 Chemical Reactions and Equations 

Which of the following salts false to give brown gas on heating?

(1) Lead nitrate
(2) Lithium nitrate
(3) Magnesium nitrate
(4) Postassium nitrate

6 Chemical Reactions and Equations 

A strip of copper is placed in four different colourless salt solution. The salt solutions are NaNO₃, Zn(NO₃)₂ , Mg(NO₃)₂, , AgNO₃  Which one of the solution will finally turn blue

(1) AgNO₃ 
(2) Zn(NO₃)₂ 
(3) Mg(NO₃)₂ 
(4) NaNO₃

7 Chemical Reactions and Equations 

Aquaregia can dissolve gold because

(1) it contains an oxidant conc. H₂SO₄
(2) It is 3 : 1 mixture of conc. HNO₃  and conc. HCl
(3) It contains a strong reducing agent
(4) It contains nascent Cl