Which of the following substances represents calcium chlorite?

Which of the following has the minimum number of oxygen atoms?

Iron sulphide is heated in air to form $A$,an oxide of sulphur. $A$ is dissolved in water to give an acid. The basicity of this acid is:

Which of the following formulas is correctly represented according to Stock notation?

If lattice enthalpy and hydration enthalpy of $KCl$ are $699 \ kJ \ mol^{-1}$ and $-681.8 \ kJ \ mol^{-1}$ respectively,what is the enthalpy of solution of $KCl$?

What quantity (in $mL$) of a $45\%$ acid solution of a mono-protic strong acid must be mixed with a $20\%$ solution of the same acid to produce $800 \ mL$ of a $29.875\%$ acid solution?