Question

12. Consider the following statements. Identify which of these are correct?

I. 1 mole means 6.023 × 1023 particles

II. Molar mass is mass of one molecule

III. Molar mass is mass of one mole of substance

IV. Molar mass is molecular mass expressed in grams

Choose the correct answer from the options given below:

• A. I, II
• B. I, III, IV
• C. II, IV
• D. I, II, III

Answer 1

Answer: (B)

I, III, IV

Answer 2

• Statement I: Correct. One mole is defined as the amount of substance containing $6.022 \times 10^{23}$ elementary entities (Avogadro's number).
• Statement II: Incorrect. Molar mass is the mass of one mole of a substance, not the mass of one molecule. The mass of one molecule is its molecular mass.
• Statement III: Correct. This is the fundamental definition of molar mass.
• Statement IV: Correct. The molecular mass of a substance, when expressed in grams, is numerically equal to its molar mass in grams per mole. For example, molecular mass of H₂O is approx. 18 amu, and its molar mass is 18 g/mol.