1
MCQ (Single Correct Answer)

AIPMT 2011 Prelims

The pairs of species of oxygen and their magnetic behavior are noted below. Which of the following presents the correct description?
A
O$$_2^ - $$, O$$_2^{2 - }$$ - Both diamagnetic
B
O+, O$$_2^{2 - }$$ - Both paramagnetic
C
O$$_2^{ + }$$, O2 - Both paramagnetic
D
O, O$$_2^{2 - }$$ - Both paramagnetic

Explanation

$$O_2^+$$ and $$O_2$$ are paramagnetic in nature as they contain one and two unpaired electrons respectively.
2
MCQ (Single Correct Answer)

AIPMT 2011 Prelims

Which of the two ions from the list given below that have the geometry that is explained by the same hybridization of orbitals, NO$$_2^ - $$. NO$$_3^ - $$, NH$$_2^ - $$, NH$$_4^ + $$, SCN$$-$$?
A
NO$$_2^ - $$ and NO$$_3^ - $$
B
NH$$_4^ + $$ and NO$$_3^ - $$
C
SCN$$-$$ and NH$$_2^ - $$
D
NO$$_2^ - $$ and NH$$_2^ - $$

Explanation

Ions Hybridisation
$$NO_2^-$$ $$sp^2$$
$$NO_3^-$$ $$sp^2$$
$$NH_2^-$$ $$sp^3$$
$$NH_4^+$$ $$sp^3$$
$$SCN^-$$ sp
3
MCQ (Single Correct Answer)

AIPMT 2011 Prelims

The correct order of increasing bond length of C $$-$$ H, C $$-$$ O, C $$-$$ C and C$$=$$C is
A
C $$-$$ H < C$$=$$C < C $$-$$ O < C $$-$$ C
B
C $$-$$ C < C$$=$$C < C $$-$$ O < C $$-$$ H
C
C $$-$$ O < C $$-$$ H < C $$-$$ C < C$$=$$C
D
C $$-$$ H < C $$-$$ O < C $$-$$ C < C$$=$$C

Explanation

Increasing order of bond length is

$$\mathop {C - H}\limits_{107\,pm} < \mathop {C = C}\limits_{134\,pm} < \mathop {C - O}\limits_{141\,pm} < \mathop {C - C}\limits_{134\,pm} $$
4
MCQ (Single Correct Answer)

AIPMT 2011 Prelims

Which of the following has the minimum bond length ?
A
O2+
B
O2$$-$$
C
O22$$-$$
D
O2

Explanation

Electronic configuration
O2 : $$\sigma 1{s^2}{\sigma ^*}1{s^2}\sigma 2{s^2}{\sigma ^*}2{s^2}\sigma 2p_z^2\pi 2p_y^2{\pi ^*}2p_y^1{\pi ^*}2p_z^1$$

Bond order = $${1 \over 2}\left( {8 - 4} \right)$$ = 2

O2+ : Bond order = $${1 \over 2}\left( {8 - 3} \right)$$ = 2.5

O2- : Bond order = $${1 \over 2}\left( {8 - 5} \right)$$ = 1.5

O22- : Bond order = $${1 \over 2}\left( {8 - 6} \right)$$ = 1

As bond order increases, bond length decreases.

EXAM MAP

Joint Entrance Examination

JEE Advanced JEE Main

Medical

NEET

Graduate Aptitude Test in Engineering

GATE CE GATE ECE GATE ME GATE IN GATE EE GATE CSE GATE PI