Question

Komal was sitting in the chemistry lab. She wanted to practically check about evaporation, the concept explained by her teacher in the last class.

So, She took two beakers A and B and poured dimethyl ether in A and ethyl alcohol in B. She left the beakers for evaporation to happen. Which of the beaker will have faster rate of evaporation and why?

• A. A, because intermolecular forces of attraction is less.
• B. B, because intermolecular forces of attraction is less
• C. A, because intermolecular forces of attraction is more
• D. B, because intermolecular forces of attraction is more.

Answer 1

The correct option is A A, because intermolecular forces of attraction is less.

Having difficulty in answering this question?

Then Let me ask you a question.

Will liquids having weaker intermolecular forces of attraction find it easier than Liquids having stronger intermolecular forces of attraction to pass into gaseous phase from the Liquid phase?

$\to$ Yes, They will find it easier. Why?

We know that liquids have stronger IMFs of attraction while gases have very weak IMFs of attraction.

Now, within liquids if any liquid will have weaker IMFs, then it will be easier for that liquid to pass into gas (which have even lesser IMFs of attraction)

So, now we know Liquids having weaker IMFs of attraction will find it easy to pass into gaseous phase.

Let’s come back to the question.

We have
Dimethyl ether $\Rightarrow$

Ethyl alcohol $\Rightarrow C{H}_{3}C{H}_{2}OH$

Dimethyl ether $\Rightarrow Lesspolarity\Rightarrow NoH-bonding\Rightarrow$ Mostly London Dispersion Forces

Ethyl alcohol

Having difficulty in answering this question?

Then Let me ask you a question.

Liquids having weaker intermolecular forces of attraction will find it easier than Liquids having stronger intermolecular forces of attraction to pass into gaseous phase than the Liquid phase?

$\to$ Yes, They will find it easier. Why?

We know that liquids have stronger IMFs of attraction while gases have very weak IMFs of attraction.

Now, within liquids if any liquid will have weaker IMFs, then it will be easier for that liquid to pass into gas (which have even lesser IMFs of attraction).

So, now we know liquids having weaker IMFs of attraction will find it easy to pass into gaseous phase.

Let’s come back to the question.

We have
Dimethyl ether $\Rightarrow$

Ethyl alcohol $\Rightarrow C{H}_{3}C{H}_{2}OH$

Dimethyl ether $\Rightarrow Lesspolarity\Rightarrow NoH-bonding\Rightarrow$ Mostly London Dispersion Forces

Ethyl alcohol $\Rightarrow$ H-bonding

$\Rightarrow$ Dimethyl ether $\Rightarrow$ Weaker IMFs of attraction

Ethyl alcohol $\Rightarrow$ Stronger IMFs of attraction

Therefore, the rate of evaporation will be more in case of dimethyl ether because of weaker IMFs of attraction.