(a) D = M/V
The volume increases, with the increase of temperature. Therefore, density decrease with the rise of temperature.
(b) Surface tension diminishes with rise in temperature.
(c) Viscosity decreases with the increase of temperature. This is because, increase in temperature increases the average kinetic energy of molecules which multiplies the attractive forces between them.
(d) As the temperature of a liquid is increased, the vapour pressure increases.