AIPMT 2015 | p-Block Elements Question 46 | Chemistry

The formation of the oxide ion, O^2$$-$$_(g) from oxygen atom requires first an exthermic and then an endothermic step as shown below:
O_(g) + e^$$-$$ $$ \to $$ O^$$-$$_(g); $$\Delta $$_fH^o = $$-$$141 kJ mol^$$-$$1

O^$$-$$_(g) + e^$$-$$ $$ \to $$ O^2$$-$$_(g); $$\Delta $$_fH^o = +780 kJ mol^$$-$$1

Thus, process of formation of O^2$$-$$ is isoelectronic with neon. It is due to the fact that,

O^$$-$$ ion has comparatively smaller size than oxygen atom

oxygen is more electronegative

addition of electron in oxygen results in larger size of the ion

electron repulsion outweighs the stability gained by achieving noble gas configuration.

AIPMT 2015 Cancelled Paper

MCQ (Single Correct Answer)

-1

Nitrogen dioxide and sulphur dioxide have some properties in common . Which property is shown by one of these compounds , but not by the other?

Is soluble in water.

Is used as a food preservative.

Forms 'acid-rain'.

Is a reducing agent.

AIPMT 2014

MCQ (Single Correct Answer)

-1

Acidity of diprotic acids in aqueous solutions increases in the order

H₂S < H₂Se < H₂Te

H₂Se < H₂S < H₂Te

H₂Te < H₂S < H₂Se

H₂Se < H₂Te < H₂S

NEET 2013 (Karnataka)

MCQ (Single Correct Answer)

-1

Identify the incorrect statement, regarding the molecule XeO₄ :

XeO₄ molecule is square planar.

There are four p$$\pi $$ - d$$\pi $$ bonds.

There are four sp³ - p, $$\sigma $$ bonds.

XeO₄ molecule is tetrahedral.

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Biology

Zoology

Human Health and Diseases Body Fluids and Its Circulation Locomotion and Movement Neural Control and Coordination Reproduction in Organisms Reproductive Health Structural Organisation in Animals Digestion and Absorption Excretory Products and Their Elimination Chemical Coordination and Integration Human Reproduction Animal Kingdom Breathing and Exchange of Gases Evolution