A solution of palmitic acid (Molar mass = 256) in Benzene contain 5.12 g of acid per litre of solution. When this solution is dropped on a water surface, the Benzene evaporates and acid forms a monolayer film of solid type. If `500 cm^(2)` are is to be covered by a monolayer, then find X, where `X = (V)/(100)`, when V is volume required of solution. The area covered by 1 molecule `= 0.2 nm^(2)`.

Answer

`2`

Explanation

Let V litre of palmitic acid is required.
Number of molecules ` = (5.12 V)/(256) xx 6.023 xx 10^(23) = 1.2 xx 10^(22) V`
Area covered `= (1.2 xx 10^(22) V)(0.2 xx 10^(-14) cm^(2)) = 2.4 xx 10^(7) V cm^(2)`
`2.4 xx 10^(7) V cm^(2) = 500 cm^(2)`
`V = 0.02 cm^(3) = (2)/(100) cm^(3)`
X = 2