When a cell is kept in 0.5 M solution is sucrose, its volume does not change. If the same cell is  placed in 0.5 M solution of NaCl, the volume of cell will 

A molar solution of sodium chloride has twice the osmotic concentration than that of sucrose. This is because sodium chloride is an electrolyte and dissociates almost completely  into Na⁺ and C l^- ions. Whereas sucrose or glucose molecules are non electrolytes and donot dissociate in water.