1

AIPMT 2012 Prelims

Sulphur trioxide can be obtained by which of the following reaction?
A
CaSO4 + C $\buildrel \Delta \over \longrightarrow$
B
Fe2(SO4)3 $\buildrel \Delta \over \longrightarrow$
C
S + H2SO4 $\buildrel \Delta \over \longrightarrow$
D
H2SO4 + PCl5 $\buildrel \Delta \over \longrightarrow$

Explanation

Fe2(SO4)3 $\buildrel \Delta \over \longrightarrow$ Fe2O3 + 3SO3
2

AIPMT 2012 Prelims

In which of the following compounds, nitrogen exhibits highest oxidation state?
A
N2H4
B
NH3
C
N3H
D
NH2OH

Explanation

N2H4 : Oxidation state of N = – 2

NH3 : Oxidation state of N = – 3

N3H : Oxidation state of N = – 1/3

NH2OH : Oxidation state of N = – 1

$\therefore$ Highest oxidation state = –1/3
3

AIPMT 2012 Prelims

Which of the following statements is not valid for oxoacids of phosphorus?
A
Orthophosphoric acid is used in the manufacture of triple superphosphate.
B
Hypophosphorous acid is a diprotic acid.
C
All oxoacids contain tetrahedral four coordinated phosphorus.
D
All oxoacids contain atleast one P$=$O unit and one P$-$OH group.

Explanation

Hypophosphorus acid is a monoprotic acid.
4

AIPMT 2011 Prelims

Name the two type of the structure of silicate in which one oxygen atom of [SiO4]4$-$ is shared?
A
Linear chain silicate
B
Sheet silicate
C
Pyrosilicate
D
Three dimensional

Explanation

Pyrosilicate contains two units of SiO44– joined along a corner containing oxygen atom.