The number of moles of water belonging in two liter water provided its density is 1gm/cc at 25 degree centigrade is?

Question

a)55.5

b)2*55.5

c)55.5/2

d)55.5/3

Answer 1

Given : 

The density of water is 1g/cc, so if you do dimensional analysis, you can find that in 1 L of water, there is 55.56 mol. 
Water density is: 1g/cc

1ml * 1g/ml = 1g of water in 1 ml. 

Now,
Water molecular weight, about: 18g/mol

1g * 1mol/18g = 1/18 moles = about 0.0556 moles in 1ml (=1g) of water. 
So, in 1 L, there will be 55.6 moles.

Therefore, in 2L of water there will be 2*55.6 moles

So, the correct answer is (b)