Chemical Bonding and Molecular Structure · Question 105

In X-H Y, X and Y both are electronegative elements. Then

1. electron density on X will increase and on H will decrease
2. in both electron density will increase
3. in both electron density will decrease
4. on X electron density will decrease and on H will increase.

Answer

(1) electron density on X will increase and on H will decrease

Solution

In the X–H bond, the more electronegative X pulls the shared electron pair towards itself.

⇒ X acquires a partial negative charge ( -): electron density on X increases.

⇒ H acquires a partial positive charge ( +): electron density on H decreases.

∴ This H + is then attracted by the electronegative atom Y, forming the hydrogen bond X --H + Y -.

Answer: (1)