The equilibrium composition for the reaction $$\mathrm{PCl}_{3}+\mathrm{Cl}_{2} \rightleftharpoons \mathrm{PCl}_{5}$$ at $$298 \mathrm{~K}$$ is given below:

$$\left[\mathrm{PCl}_{3}\right]_{\mathrm{eq}}=0.2 \mathrm{~mol} \mathrm{~L}^{-1},\left[\mathrm{Cl}_{2}\right]_{\mathrm{eq}}=0.1 \mathrm{~mol} \mathrm{~L}^{-1},\left[\mathrm{PCl}_{5}\right]_{\mathrm{eq}}=0.40 \mathrm{~mol} \mathrm{~L}^{-1}$$

If $$0.2 \mathrm{~mol}$$ of $$\mathrm{Cl}_{2}$$ is added at the same temperature, the equilibrium concentrations of $$\mathrm{PCl}_{5}$$ is __________ $$\times 10^{-2} \mathrm{~mol} \mathrm{~L}^{-1}$$

Given : $$\mathrm{K}_{\mathrm{c}}$$ for the reaction at $$298 \mathrm{~K}$$ is 20

In an ice crystal, each water molecule is hydrogen bonded to ____________ neighbouring molecules.

Among the following, the number of compounds which will give positive iodoform reaction is _________

(a) 1-Phenylbutan-2-one

(b) 2-Methylbutan-2-ol

(c) 3-Methylbutan-2-ol

(d) 1-Phenylethanol

(e) 3,3-dimethylbutan-2-one

(f) 1-Phenylpropan-2-ol

Number of crystal systems from the following where body centred unit cell can be found, is ____________.

Cubic, tetragonal, orthorhombic, hexagonal, rhombohedral, monoclinic, triclinic