Question

nacl may be spread on an icy sidewalk in order to melt ice equimolar amounts of cacl2 are even more effective. explain both

Answer 1

NaCl gives two moles of ions as

1NaCl   <====>   1Na+      +       1Cl-      (total two ions)

Whereasd, CaCl2 gives three moles of ions as:

1CaCl2    <=====>     1Ca2+        +       2Cl-         (total three ions)

SO, the number of moles of ions are more in CaCl2 hence, it will provide more depression in freezing point than NaCl with equimolar amounts.