The following is the correct order of chemical reactivity with water according to electrochemical series-

1. K>Mg>Cu>Zn                                     

2. K>Mg>Zn>Cu

3. Cu>Zn>K>Mg                                     

4. Mg>K>Cu>Zn

In the reaction $\mathrm{M}+{\mathrm{O}}_2\to {\mathrm{MO}}_2$ (superoxide) the metal is -

1. Li                 

2. Na

3. K                 

4. Ba 

The reaction of sodium with water is highly exothermic. The rate of reaction can be lowered by-

(1) Decreasing the temperature 

(2) Mixing with alcohol

(3) Mixing with acetic acid 

(4) Making an amalgam

Sodium reacts with water less vigorously than potassium because-

1. It has a higher atomic weight.

2. It is less electropositive .

3. It is more electronegative. 

4. It is a metal .

The correct relation about the density of Na and K is 

1. Na > K                                                     

2. Na = K

3. K > Na                                                     

4. Li > K

Which of the following does not give an oxide on heating-

(1) $MgC{O}_3$                                                   

(2) $L{i}_{2}C{O}_3$

(3) $ZnC{O}_3$                                                   

(4) $K_{2}C{O}_3$ 

The reason for a lower basicity of hydroxides of alkaline earth metals than alkali metals is : 

1. Alkali metals form ionic compounds.

2. The bond strength of oxygen is more for alkali metals.

3. The electropositivity of alkali metals is more than alkaline earth metals.

4. The electropositivity of alkali metals is less than alkaline earth metals.

In $K^{+}{F}^{-}$ ionic radius of $F^{-}$ is more while atomic radius of $K^{+}$ is –

(1) Less than $F^{-}$

(2) More than $F^{-}$

(3) Equal to $F^{-}$

(4) None of these

Lattice energy is lowest for –

1. LiF                                                       

2. NaCl

3. KBr                                                       

4. CsI

MgO is a-

(1) Acidic oxide                                     

(2) Basic oxide

(3) Neutral oxide                                   

(4) Amphoteric oxide