1

### NEET 2016 Phase 2

AlF3 is soluble in HF only in presence of KF. It is due to the formation of
A
K3[AlF3H3]
B
K3[AlF6]
C
AlH3
D
K[AlF3H]

## Explanation

AlF3 is insoluble in anhydrous HF because the F ions are not available in hydrogen bonded HF but, it becomes soluble in presence of little amount of KF due to formation of complex, K3[AIF6].

AIF3 + 3KF $\to$ K3[AIF6].
2

### NEET 2016 Phase 2

Boric acid is an acid because its molecule
A
contains replaceable H+ ion
B
gives up a proton
C
accepts OH$-$ from water releasing proton
D
combines with proton from water molecule.

## Explanation

Boric acid behaves as a Lewis acid, by accepting a pair of electrons from OH ion of water thereby releasing a proton.

H-OH+B(OH)3 $\to$ [B(OH)4] + H+
3

### AIPMT 2015

Which of the statements given below is incorrect?
A
O3 molecule is bent.
B
ONF is isoelectronic with O2N
C
OF2 is an oxides of fluorine.
D
Cl2O7 is an anhydride of perchloric acid.

## Explanation

OF2 (oxygen difluoride) is a fluoride of oxygen because fluorine is more electronegative than oxygen.
4

### AIPMT 2015 Cancelled Paper

Nitrogen dioxide and sulphur dioxide have some properties in common . Which property is shown by one of these compounds , but not by the other?
A
Is soluble in water.
B
Is used as a food preservative.
C
Forms 'acid-rain'.
D
Is a reducing agent.

## Explanation

SO2 is widely used in food and drinks industries for its property as a preservative and antioxidant while NO2 is not used as food preservative.