Question

2

Answer 1

Vapour pressure is determine by the rate of collisions of the molecules to the walls of the container.
I would deduce that if the particle consists of a molecule, the vapour pressure will be low as the molecule is heavier than an atom, like Chlorine, thus having lower kinetic energy and subsequently a lower amount of collisions.
Now, to determine gases formed, imagine the decomposition of each and every compound and see which one has molecules and which one has gas compounds.
NB: I will not balance, though there is no need.
For sucrose:\[C _{12}H _{22}O _{11}\rightarrow CO _{2}+H _{2}O\]
For Calcium nitrate:\[Ca(NO _{3})_{2}\rightarrow CaO+NO _{2}+O _{2} \]
For Nikel Sulphate:\[NiSO _{4}\rightarrow NiO+SO _{3} \]
For Lithium Phosphate(III):\[Li _{3} PO _{4}\rightarrow LiO+P _{2}O _{5} \]
For Brine:\[NaCl \rightarrow Na+Cl _{2} \]
Conclusively, the alternative of Calcium Nitrate will be the best as there are two gases, where one of them is an a single molecule/ideal, that has the highest kinetic energy, contributing more a higher number of collisions.

Answer 2

Hope it helped.