Gold number of gum arabic is 0.15. The amount of gum arabic required to protect 100mL of red gold sol from coagulated bu 10mL of 10% NaCl solution is
Answer & explanation
Correct answer: option 4
By definition, amount required for 10mL of gold sol = 0.15mg
∴ Amount required for 100mL of gold sol = 0.15 x 10 = 1.5mg