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 :

The correct statement about the reaction of water with fluorine is:

The structure of the common form of ice is :

Water acts as a base in -

1. Reaction with ${\mathrm{H}}_2\mathrm{S}$

2. Reaction with ${\mathrm{NH}}_3$

3. Reaction with NaOH

4. All of the above

‘Demineralised’ water can be obtained by :

Demineralized or distilled water is not useful for drinking purposes because -

1. Demineralised water contains all insoluble minerals. 

2. Demineralised water is free of all soluble minerals. 

3. Demineralised water contains soluble minerals. 

4. Demineralised water contains soluble anion only.

Water is important in the biosphere and biological systems because :

The properties of water which make it useful as a solvent is/are -

1. A high value of dielectric constant  

2. A high value of dipole moment

3. A high value of lattice energy

4. Both '1' and '2'

D2O cannot be used for drinking purposes, because - 

1.  it increases the rate of catabolic reactions 

2. it slows the rate of anabolic and catabolic reactions

3. it slows the rate of anabolic reactions.

4. it increases the rate of a reaction.