Why do colours and lubricating oil have less surface tension?

Two glass plates of area $10^{-2} \,m^2$ have a $10 \,cm$ thick water film between them. The surface tension of water is $70 \times 10^{-3} \,N/m$. The force required to separate the two glass plates from each other is (in $\,N$)

The property utilized in the manufacture of lead shots is

Small liquid drops assume a spherical shape because

Is surface tension a vector or scalar? Explain.

$A$ needle is $7 \ cm$ long. Assuming that the needle is not wetted by water,what is the weight of the needle,so that it floats on water (in $g \ wt$)? $\left[T = \text{surface tension of water} = 70 \ dyne/cm\right]$ [acceleration due to gravity $= 980 \ cm \ s^{-2}$]