Number of moles of copper used when

(i) Copper reacts with dilute nitric acid

(ii) Copper reacts with concentrated nitric acid

are respectively:-

1. 1,1

2. 1,3

3. 3,1

4. 3,3

An element that does not have a d-orbital is:

The least basic compound is:

1. BiH₃

2. AsH₃

3. PH₃

4. NH₃

Incorrect statement about red phosphorus is:

1. It is hard and crystalline.

2. It is poisonous.

3. It is less reactive than white phosphorus.

4. It is insoluble in water.

Which element exhibits the highest catenation property?

1. Phosphorus

2. Nitrogen

3. Antimony

4. Bismuth

The gas released on heating H₃PO₃ is 

1. Oxygen

2. Phosphine

3. Hydrogen

4. Water vapours

PCl₅ acts as

1. Reducing agent

2. Oxidising agent

3. Dehydrating Agent

4. None of the above.

The electron gain enthalpy values for O → O^– and O → O^2– are –141 and 702 kJ  mol^-1 , respectively. The correct statement about the formation of oxides is-

The group which contains the strongest oxidizing agent is-

1. Group 15

2. Group 16

3. Group 17

4. Group 18

 Halogen that forms only one oxoacid is :

1. Chlorine

2. Fluorine

3. Bromine

4. Iodine