236) Which of the following indicators is appropriate in the titration of NH₄OH and strong acid?

237) What will be the mole fraction of acetone in the solution formed by 1.8 gm of water and 2.9 gm of acetone?

238) Value of pK_a for acetic acid at 25^oC is 4.75. What will be the pH value of the solution in which ratio of concentration of sodium acetate and acetic acid is 10?

239) Phenolphthalein gives which of the following colours in acidic medium?

240) If pK_{a of acetic acid at 25^oC is 4.75, then determine the pH of that solution in which 0.02M sodium acetate and acetic acid are present:}