4. Na2SO4. 10H2O crystals are formed by cooling 100 Kg of 30% by weight aqueous solution of Na2SO4. The final concentration of the solute in the solution is 10%. The weight of crystals is
5. A perfectly insulated container of volume V is divided into two equal halves by a partition. One side is under vacuum, while the other side has one mole of an ideal gas (with constant heat capacity) at 298 K. If the partition is broken, the final temperature of the gas in the container
Correct Answer: Hess's law of constant heat summation
9. Pick out the wrong statement.
Options
A. To make 100 kg of a solution containing 40% salt by mixing solution A (containing 25% salt) and solution B (containing 50% salt), the amount of solution A required is 40 kg.
B. 1.2 gm atoms of carbon and 1.5 gm moles of oxygen are reacted to give 1 gm mole of carbon dioxide. The limiting reactant is carbon. The percent excess reactant supplied is 25.
C. A gas bubble at a pressure of Pg is passed through a solvent with a saturation vapour pressure of Ps. If the time of passage of the bubble is long and air is insoluble in the solvent, the mole fraction of solvent in the bubble will be equal to Ps/Pg.
D. A supersaturated solution of a sparingly soluble solute, at a concentration of C, is being fed to a crystalliser at a volumetric flow rate of V. The solubility .of the solute is C1. The output rate of solids from an efficient crystalliser is (C + C1) V.
Correct Answer: A supersaturated solution of a sparingly soluble solute, at a concentration of C, is being fed to a crystalliser at a volumetric flow rate of V. The solubility .of the solute is C1. The output rate of solids from an efficient crystalliser is (C + C1) V.