उत्तर : 2. "18 gms"
व्याख्या :

Answer: B) 18 gms Explanation: The molar mass of H2O can be calculated as the following. M(H2O)= [2 x M(H)] + [M(O)]. And we know that M(H) = 1g/mol, M(O) = 16g/mol. So, M(H2O)= 2x1 + 16 = 18g/mol, That means 1 mole of H2O contains 18g.   Hence, one mole of H2O corresponds to 18 grams.