Which of the following solvents reduces the environmental pollution?

What is the number of electrons present in d-subshell if its atomic number is 27 and oxidation state is +2 ?

What is the volume occupied by 1 molecule of water, if its density is $1 \mathrm{~g} \mathrm{~cm}^{-3}$ ?

Identify the reason for the solubility of polar solute in polar solvent from the following.