Q45 / 180 · NEET 2018 · Chemistry

In which case the number of molecules of water maximum?

  • A
    0.00224 L of water vapours at 1 atm and 273 K.
  • B
    0.18 g of water.
  • Correct answer
    C
    18 mL of water.
  • D
    10-3 mol of water.

Solution

(i) 18 mL water:

As  dH2O=1g/mL So   WH2O=18g

nH2O=1818=1

Molecules =1×NA

(ii) 0.18 g of water:

nH2O=0.1818=0.01

H2O molecules=0.01×NA

(iii)  (VH2O (g))STP=0.00224 L

nH2O=V22.4=0.0022422.4=0.0001

Molecules =0.0001×NA

(iv)   nH2O=10-3

H2O molecules=10-3×NA

Hence, the correct answer is option: 'C'.

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