Good Chemistry Questions Essay

A student was assigned a certain task by his teacher in chemistry lab. During the experiment, student dropped the flask containing 250 ml, 3 molar NaOH solution. Due to this 50 ml of solution out of 250 ml, had fallen on the floor. Thinking that teacher may punish him for this mistake, he replenished the left over solution with 50 ml of water. The new molarity of NdOH solution will be. (A) 2M (8) 3M (C) 2. 5 M (D) 2. 4 M which of the following molarity values of Ions In a aqueous solution ot 5. 85 % w/v Nacl, 5. 5% wiv cac12 and wiv NaOH are correct [Na = 23, Cl = 35. , ca = 40, O = 161 (A) [Cl-l] = 2M (B) [Na+] = 1M (C) [G2+J = OS M (D) [OH-I = 1. 5 M 3. For an Ideal binary solution with PA O which relation between XA (mole fraction of A In liquid phase) and YA (mole fraction of A in vapour phase) is correct , XB and YB are mole fraction of B in liquid and vapour phase respectively : (Glven : PA 0) x (D) XA YA XB and YB cannot be correlated (XA YA XB) 4. In which case vant Hoff factor Is maximum ? (A) KCI, ionised (B) K2S04, ionised (C) snC14. ionised (D) Fec13, Ionised 5.

Solution having osmotic pressure nearer to that of an equlmolar solution of is: (A) Na2S04 (8) Bac12 (C) (D)C12 H22011 6. (a) Two aqueous solutions, one of the Nacl In water (A) and the other of C8H1502Na in water (3) are isotonic. If WA and w3 are weight fractions of NaCl and C8H1502Na in solution A and B respectively. then (assuming that both the salts dissociate completely) : (A) WA > WB (8) WA = WB (C) WA < WB (D) none of these 6(b). An electrolyte A gives 3 Ions and 3 Is a non-electrolyte. If 0. 1 M solution of 3 produces an osmotic pressure P, then 0. M solution of A will produce an osmotic pressure, assuming that the electrolyte Is completely Ionised (A) 1. 5 P (3) P (C) 0. 5 P (D) 0. 75 P 7. The osmotic pressure of equimolar solutions of BaC12. NaCl and glucose will be in (C) Naci > sac12 > glucose (D) Naci > glucose > sac12 8. A 1. 2% w/v of solution of NaCl is isotonic with 7. 2% w/v of solution of glucose. Calculate the van’t Hoffs factor of NaCl solution. (A) 2. 36 (B) 1. 50 (C) 1. 95 (D) 1. 00 9. The relative lowering of vapour pressure produced by dissolving 71. 5 gof a substance in 1000 g of water is 0. 713. The molecular weight of the substance will be (A) 18. 0 (B) 342 (C) 60 (D) 180 10. A solution is obtained by dissolving 12 gof urea (mol. wt. 60) in a litre of water. Another solution is obtained by dissolving 68. 4 g of cane sugar (mol. wt. 342) in a litre of water at are the same temperature. The lowering of vapour pressure in the first solution is (A) Same as that of 2nd solution (B) Nearly one-fifth of the 2nd solution (C) Double that of 2nd solution (D) Nearly five times that of 2nd solution 11. A mixture has 18g water and 414g ethanol.

The mole fraction of water in mixture is (assume ideal behaviour of the mixture) (A) 0. 1 (B) 0. 4 (C) 0. 7 (D) 0. 9 12. If 1 M and 2. 5 litre NaOH solution is mixed with another 0. 5 M and 3 litre NaOH solution, then molarity of the resultant solution will be : (A) 1. 0 M (B) 0. 73 M (C) 0. 80 M (D) 0. 50 M 13. What is the molarity of H2 S04 solution, that has density 1. 84 gm/cc at 350 C and contains solute by weight (A) 4. 18 M (B) 8. 14 M (C) 18. 4 M (D) 18 M 14. The amount of NaOH is gms in 250cm3 of a 0. 100M NaOH solution would be (A) 4 gm (B) 2 gm (C) 1 gm (D) 2. 5 gm