Question

Which one of the following ionic compounds is soluble in water?

NH4C2H3O2

AgCl

BaCO3

PbSO4

Answer 1

Which one of the following ionic compounds is soluble in water?

Only NH4C2H3O2 is soluble in water

and rest all are insoluble in water

Explanation

NH4C2H3O2 is an ionic compound which are usually soluble in H2O

a thumb of rule for knowing the solubility of chemicals is that generally all compounds of silver do not dissolve in water or have limited solubility in it. So AgCl is insoluble in water

Most insoluble ions include OH-, CO3(2-), PO4(3-), S(2-). These, if they are soluble, are most likely weak and can bond and split in whatever solution it happens to be in.

So BaCO3 is insoluble in water

There are two factors that need to be looked at for solubility : Hydration enthalpy and lattice enthalpy. The lattice enthalpy of the sulphate compounds increases down the group as the force of attraction between the anions and cations increases (bigger Pb molecules bond easier with large sulphate molecules) hence the compounds down the group (Lead sulphate) hence less prone to solubility in water as too much energy is required to break this bond.

So PbSO4 is insoluble in water