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1

### AIPMT 2012 Prelims

The pair of species with the same bond order is
A
O$$_2^{2 - }$$, B2
B
O$$_2^{ + }$$, NO+
C
NO, CO
D
N2, O2

## Explanation

O2- $$\to$$ 1

B2 $$\to$$ 1

O2+ $$\to$$ 2.5

NO+ $$\to$$ 3

NO $$\to$$ 2.5

CO $$\to$$ 3

N2 $$\to$$ 3

O2 $$\to$$ 2
2

### AIPMT 2012 Prelims

Bond order of 1.5 is shown by
A
O2+
B
O2$$-$$
C
O22$$-$$
D
O2

## Explanation

Configuration of O2

$$\sigma 1{s^2}{\sigma ^*}1{s^2}\sigma 2{s^2}{\sigma ^*}2{s^2}\sigma 2p_z^2\pi 2p_y^2{\pi ^*}2p_x^1{\pi ^*}2p_y^1$$

Bond order = $${{No.\,of\,{e^ - }\,in\,bonding\,M.O - No.\,of\,{e^ - }\,in\,antibonding\,M.O} \over 2}$$

Bond order of O2+ = $${{10 - 5} \over 2}$$ = 2.5

Bond order of O2- = $${{10 - 7} \over 2}$$ = 1.5

Bond order of O22- = $${{10 - 8} \over 2}$$ = 1

Bond order of O2 = $${{10 - 6} \over 2}$$ = 2
3

### AIPMT 2012 Prelims

Which of the following species contains three bond pairs and one lone pair arround the central atom ?
A
H2O
B
BF3
C
NH2$$-$$
D
PCl3

## Explanation

4

### AIPMT 2012 Prelims

Which one of the following pairs is isostructural (i.e., having the same shape and hybridization) ?
A
[BCl3 and BrCl3]
B
[NH3 and NO$$_3^ -$$]
C
[NF3 and BF3]
D
[BF$$_4^ -$$ and NH$$_4^ +$$]

## Explanation

BCl3 $$\Rightarrow$$ sp2, trigonal planar

BrCl3 $$\Rightarrow$$ sp3d, T-shaped

NH3 $$\Rightarrow$$ sp3, pyramidal

NO3- $$\Rightarrow$$ sp2, trigonal planar

NF3 $$\Rightarrow$$ sp3, pyramidal

BF3 $$\Rightarrow$$ sp2, trigonal planar

BF4- $$\Rightarrow$$ sp3, tetrahedral

NH4- $$\Rightarrow$$ sp3, tetrahedral

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