निम्नलिखित में से कौन सा गणितीय सूत्र द्रव्यमान प्रतिशत द्वारा विलयन की सांद्रता को सही ढंग से परिभाषित करता है?

What is the molarity of a solution prepared by dissolving 10 grams of NaOH in water to make a final volume of 250 mL? (Molar mass of NaOH = 40 g/mol)

At temperature T(K), the vapour pressure of an aqueous solution of a non-volatile solute, whose mole fraction is 0.02, is found to be 34.65 mm Hg. What is the vapour pressure (in mm Hg) of pure water at the same temperature?