2 Kg of ice at -20 degree C is mixed with 5Kg of water 20 degree C in an insulating vessel having negligible heat capacity. Calculate the final mass of water remaining in the comtainer. It is given thet the specific heats of water and ice are 1Kcal/kg/degree C and 0.5Kcal/kg/degree C while latent heat of fusion of ice is 80 kcal/kg

Dear Nishan,
apply the formula of mcT and at first calculate the amount of heat losed by water at 0 degree.
the calculate the amount of heat gained by ice to go to 0 degree.
now subtract the second from the first to get heat left for absorption.
equate this heat to (mL)=latent heat ...and get the mass of  new water formed.
you will get it as 1 kg.
hence the ans is 5+1=6 kg(ANS)
Regards.