Among the following colloids, the number of colloids having negatively charged colloidal particles, — Surface Chemistry Chemistry Question
Question
Among the following colloids, the number of colloids having negatively charged colloidal particles, is:<br>Soap solution of sodium palmitate, sol of AgCl obtained on dissolving excess AgNO₃ into KCl solution, gold sol, Fe(OH)₃ sol, silicic acid sol, Basic dye, Acidic dye, metal sulphide sol, sol of AgCl obtained by dissolving excess KCl in AgNO₃ solution
💡 Solution & Explanation
Let us identify the charge of each sol: 1) Soap solution of sodium palmitate: Negative (palmitate anions on surface). 2) AgCl in excess AgNO₃: Positive (adsorbs Ag⁺). 3) Gold sol: Negative. 4) Fe(OH)₃ sol: Positive. 5) Silicic acid sol: Negative. 6) Basic dye: Positive. 7) Acidic dye: Negative. 8) Metal sulphide sol: Negative. 9) AgCl in excess KCl: Negative (adsorbs Cl⁻). The negatively charged sols are (1), (3), (5), (7), (8), and (9). Total = 6. Therefore, correct answer is 6.