Which cleansing agent gets precipitated in hard water?

Match List-$I$ with List-$II$ :

List-$I$ (Chemical)	List-$II$ (Used as)
$(a)$. Sucralose	$(i)$. Synthetic detergent
$(b)$. Glyceryl ester of stearic acid	$(ii)$. Artificial sweetener
$(c)$. Sodium benzoate	$(iii)$. Antiseptic
$(d)$. Bithionol	$(iv)$. Food preservative

Choose the correct match:

Which of the following statements are correct?
$a$. Aspartame is sweeter than saccharin
$b$. Shaving soaps contain glycerol to prevent drying
$c$. Salt of sorbic acid is used as a food preservative
$d$. Norethindrone is an example of an antifertility drug

Which from the following methods is $\underline{\text{NOT}}$ used to preserve food?

Which of the following statements are not correct?
$a$) Antihistamine also functions as an antacid
$b$) The shape of an active site of an enzyme does not change when the drug binds to an allosteric site
$c$) Chemical messengers communicate the message between two neurons
$d$) Potassium soaps are hard,while sodium soaps are soft to skin
The correct answer is

Identify the principle suggesting to avoid protection and deprotection of selective group for organic reactions in green chemistry.