The exact volumes of 1 M NaOH solution required to neutralise 50 mL of 1 M H₃PO₃ solution and 100 mL of 2 M H₃PO₂ solution, respectively, are :

Complete combustion of 1.80 g of an oxygen containing compound (C_xH_yO_z) gave 2.64 g of CO₂ and 1.08 g of H₂O. The percentage of oxygen in the organic compound is :

The average molar mass of chlorine is 35.5 g mol^–1. The ratio of ³⁵Cl to ³⁷Cl in naturally occuring chlorine is close to :

A solution of two components containing n₁ moles of the 1^st component and n₂ moles of the 2^nd component is prepared. M₁ and M₂ are the molecular weights of component 1 and 2 respectively. If d is the density of the solution in g mL^–1, C₂ is the molarity and x₂ is the mole fraction of the 2^nd component, then C₂ can be expressed as :