The qualitative sketches I,II and III given below show the variation of surface tension with molar concentration of three different aqueous solution `KCl,CH_(3)OH` and `CH_(3)(CH_(2))_(11)OSO_(3)NA^(+)` at room temperature. The correct assignment of the sketches is

Options

A. I: KCl II : `CH_(3)OH` III: `CH_(3) (CH_(2))_(11) OSO_(3)^(-)Na^(+)`
B. I: `CH_(3)(CH_(2))_(11) OSO_(3)^(-)Na^(+)` II: `CH_(3) OH` III KCl
C. I : KCl II : `CH_(3) (CH_(2))_(11) OSO(3)^(-) OSO_(3)^(-)Na^(+)` III : `CH_(3)OH`
D. I: `CH_(3)OH` II: KCl III : `CH_(3)(CH_(2))_(11) OSO_(3)^(-)Na^(+)`

Answer

D

Explanation

`I rarr (CH_(3)OH) rarr` It decreases the strength of intermolecular hydrogen bonding when dissolved in water, thus surface tension slightly decreases.
`II rarr (KCl) rarr` It is ionic compound, it increases the intermolecular force when dissolved in water, thus surface tension increases.
`III rarr {CH_(3) (CH_(2))_(11) OSO_(3)^(-)Na^(+)} rarr` It is detergent and works as surfacetant when dissolved in water, therefore, surface tension decreases largely