The number of P-O-P bonds in cyclic metaphosphoric acid is

Ammonia can be dried by

Polyphosphates are used as water-softening agents because they

The bonds present in $N_2{O}_{5}N\_2O\_5$ are

Which one of the following is the strongest base?

Which of the following oxides of nitrogen is a coloured gas?

Amongst the trihalides of nitrogen, which one is least basic?

The reaction of $P_{4}P\_4$ with X leads selectively to $P_4{O}_{6}P\_4O\_6$. The X is

Extra pure $N_{2}N\_2$ can be obtained by heating

Which ordering of compounds is according to the decreasing order of the oxidation state of nitrogen?