On addition of 1 ml of 10% solution of NaCl to 10 ml red gold sol in the presence of 0.025 g of the — Surface Chemistry Chemistry Question

💡 Solution & Explanation

Gold number is defined as the mass of the protective colloid in milligrams (mg). Here, mass of starch used = 0.025 g = 0.025 × 1000 mg = 25 mg. Therefore, correct answer is D.