Which of the following acids is formed when $SiF_4$ reacts with water?

Anhydrous sample of ferric chloride is prepared by heating:

Which one of the following is used as a refrigerant for ice-cream and frozen foods?

Nitrolim is

The gas which turns lime water milky is:

Consider the following statements:
$(a)$ $R_2SiO$ is the repeating unit of linear silicones.
$(b)$ $RSiCl_3$ on hydrolysis followed by dehydration gives linear silicones.
$(c)$ Silicones can be used as heat insulators.
$(d)$ Silica is soluble in $HF$.
The correct statement$(s)$ is/are: