Molality and molarity of solution are 2.5m and 2M respectively. Weight of water present  in 900 ml solution will be

i)         M = nsolute×1000vml            2=n × 1000900             n = 1.8ii)    molality=n × 1000Wsolvent        2.5 = 1.8 ×1000Wsolvent     Wsolvent  = 720g