Butter is a colloid. It is formed when

The mass of Haemoglobin in $mg$ required to protect from coagulation of $50 \ mL$ of a gold sol on adding $5 \ mL$ of $10 \% NaCl$ solution is: (Gold number of Haemoglobin $= 0.03$)

What is the potential difference between the fixed layer and the diffused layer of opposite charges called?

What is the primary test to verify whether a solution is in colloidal form or not?

When freshly precipitated $Fe(OH)_3$ is shaken with an aqueous solution of $FeCl_3$,a colloidal solution is formed. This process is known as

$X$ is a protecting colloid. The following data is obtained for preventing the coagulation of $10 \ mL$ of gold sol to which $1 \ mL$ of $10 \% NaCl$ is added. What is the gold number of '$X$'?

Expt. No.	Weight of $X$ (in $mg$) added to gold sol	Coagulation
$1$	$24$	Not prevented
$2$	$23$	Not prevented
$3$	$26$	prevented
$4$	$27$	prevented
$5$	$25$	prevented