what is the frezzing point of 21.6 grams of NiSO4 in 1.00 times 10^2 H2O
1.00 times 10^2 WHAT of H2O?
mols NiSO4 = grams/molar mass.
molality = m NiSO4 = mols/kg solvent.
Tnen delta T = i*Kf*m
i = 2 for NiSO4. You know Kf and m, solve for delta T.
Finally, subtract delta T from the normal freezing point to find the new freezing point.