Density of water is maximum at:

1. 0$°$C

2. 100 $°$C

3. 4$°$C

4. 0 K

An ionic compound is dissolved simultaneously in heavy water and ordinary water, its solubility is –

1. Larger in heavy water

2. Smaller in heavy water

3. Solubility is same in both waters

4. Smaller in simple water

${\mathrm{H}}_2\mathrm{O}$ has higher boiling point than ${\mathrm{H}}_2\mathrm{S}$ because.

(1) ${\mathrm{H}}_2\mathrm{O}$ is a smaller molecule and hence more closely packed

(2) The bond angle in ${\mathrm{H}}_2\mathrm{O}$ is more than in ${\mathrm{H}}_2\mathrm{S}$ and hence the former molecules are more tightly packed

(3) Of intermolecular hydrogen bonding in liquid ${\mathrm{H}}_2\mathrm{O}$

(4) The latent heat of vaporisation is higher for ${\mathrm{H}}_2\mathrm{O}$ than for ${\mathrm{H}}_2\mathrm{S}$

The maximum possible number of hydrogen bonds a water molecule can form is –

(1) 2                                         

(2) 4

(3) 3                                         

(4) 1

Assertion:  ${\mathrm{D}}_2\mathrm{O}$ is called heavy water.

Reason : Its degree of dissociation is high.

Of the two solvents $H_{2}O<mspace\; width="1em"></mspace>and<mspace\; width="1em"></mspace>D_{2}O$, NaCl dissolves:

(1) equally in both

(2) only in $H_{2}O$

(3) more in $D_{2}O$

(4) more in $H_{2}O$

Heavy water is ......% heavier than ordinary water

1. 11

2. 20

3. 25

4. 15

Pure water can be obtained from sea water by:

1.  Centrifugation
2.  Plasmolysis
3.  Reverse osmosis
4.  Sedimentation

 The correct order of hydrogen bonding among ${\mathrm{NH}}_3$, H2O and HF, is 

1. HF > ${\mathrm{H}}_2\mathrm{O}$ > ${\mathrm{NH}}_3$

2. ${\mathrm{H}}_2\mathrm{O}$ > HF > ${\mathrm{NH}}_3$

3. HF > ${\mathrm{NH}}_3$ > ${\mathrm{H}}_2\mathrm{O}$

4. ${\mathrm{NH}}_3$ > HF > ${\mathrm{H}}_2\mathrm{O}$

The term ’auto-protolysis’ of water means :