Answer for Q-2: it's option C i.e, both are correct! see, d=m/v
=>m=18.
no. of moles =m/M.Wt of the substance
so, no. of moles will be 18/18= 1! opt. A is correct
and now, number of molecules = number of moles × Avogadro's number
which is 1× 6.023 ×10^23 so opt. B is also correct
which means OPTION C IS THE CORRECT ANSWER!
Answer for Q-3: 1+35.5=36.5. so option B is the correct answer!
