The raincoats are made waterproof by coating them with a material,which ............

Fill in the blanks:
$(i)$ If a liquid sticks to the glass,the angle of contact for the liquid-glass interface will be ....... (acute / obtuse).
$(ii)$ The angle of contact between mercury and glass is .......... (acute / obtuse).

$A$ hydrophilic surface is characterised by the contact angle at the water-solid interface. The value of the contact angle should be:

How does the angle of contact depend on temperature?

When the temperature is increased,the angle of contact of a liquid:

If a capillary tube is dipped into a liquid and the levels of the liquid inside and outside are the same,then the angle of contact is ...... $^o$.