On addition of $1 \ mL$ of $10 \%$ $NaCl$ to $10 \ mL$ gold sol in the presence of $0.038 \ g$ of starch the coagulation is just prevented. Then the value of gold number of starch is

In the following reaction for the preparation of gold sol,$a, b, c, x, y$ and $z$ are $a AuCl_3 + b HCHO + c H_2 O \longrightarrow x Au (\text{sol}) + y HCO_2 H + z HCl$. Find the correct values for the coefficients.

Which of the following salt solutions would coagulate the colloid solution formed when $FeCl_{3}$ is added to $NaOH$ solution,at the fastest rate?

Among the electrolytes $Na_2SO_4$,$CaCl_2$,$Al_2(SO_4)_3$,and $NH_4Cl$,the most effective coagulating agent for $Sb_2S_3$ sol is

Which of the following electrolytes will have the maximum flocculation value for $Fe(OH)_3$ sol?

Identify the correct statements from the following :
$I$. Sulphur sol is an example of a multimolecular colloid.
$II$. Tyndall effect is observed when the diameter of the dispersed particles is not much smaller than the wavelength of the light used.
$III$. The process of removing a dissolved substance from a colloidal solution by means of diffusion through a suitable membrane is called peptisation.
$IV$. Eosin,gelatin are examples of negatively charged sols.