p-Block Elements (Group 15–18)

Identify the incorrect statement from the following:

1. Phosphorus, arsenic and antimony show catenation property.
2. P(C2H5)3 and As(C6H5)3 form dπ–dπ bond with transition metals.
3. Nitrogen can form dπ–pπ bond with oxygen.
4. Nitrogen can form pπ–pπ multiple bonds with itself.

Given below are two statements : In the light of the above statements, choose the most appropriate answer from the options given below :

1. Statement I is correct but Statement II is incorrect
2. Statement I is incorrect but Statement II is correct
3. Both Statement I and Statement II are correct
4. Both Statement I and Statement II are incorrect

Identify the incorrect statement.

1. PEt3 and AsPh3 as ligands can form d - d bond with transition metals
2. The N - N single bond is as strong as the P - P single bond
3. Nitrogen has unique ability to form p - p multiple bonds with nitrogen, carbon and oxygen
4. Nitrogen cannot form d - p bond as other heavier elements of its group

Which of the following reactions is a part of the large scale industrial preparation of nitric acid?

1. Cu(NO3)2 + 2NO2 + 2H2O [500 K, 9 bar]Pt 4HNO3 + Cu
2. NaNO3 + H2SO4 [500 K, 9 bar]Pt NaHSO4 + HNO3
3. 4NH3 + 5O2 (from air) [500 K, 9 bar]Pt 4NO + 6H2O
4. 4HPO3 + 2N2O5 [500 K, 9 bar]Pt 4HNO3 + P4O10

Urea reacts with water to form A which will decompose to form B. B when passed through Cu2+(aq), deep blue colour solution C is formed. What is the formula of C from the following?

1. [Cu(NH3)4]2+
2. Cu(OH)2
3. CuCO3 Cu(OH)2
4. CuSO4

Identify the incorrect statement related to PCl5 from the following :

1. Axial P–Cl bonds are longer than equatorial P–Cl bonds
2. PCl5 molecule is non-reactive
3. Three equatorial P–Cl bonds make an angle of 120° with each other
4. Two axial P–Cl bonds make an angle of 180° with each other

Which is the correct statement for the given acids?

1. Phosphinic acid is a monoprotic acid while phosphonic acid is a diprotic acid.
2. Phosphinic acid is a diprotic acid while phosphonic acid is a monoprotic acid.
3. Both are diprotic acids.
4. Both are triprotic acids.

When copper is heated with conc. HNO3 it produces

1. Cu(NO3)2, NO and NO2
2. Cu(NO3)2 and N2O
3. Cu(NO3)2 and NO2
4. Cu(NO3)2 and NO

Strong reducing behavior of H3PO2 is due to

1. high electron gain enthalpy of phosphorus
2. high oxidation state of phosphorus
3. presence of two -OH groups and one P-H bond
4. presence of one -OH group and two P-H bonds.

Which of the following statements is not valid for oxoacids of phosphorus?

1. Orthophosphoric acid is used in the manufacture of triple superphosphate.
2. Hypophosphorous acid is a diprotic acid.
3. All oxoacids contain tetrahedral four coordinated phosphorus.
4. All oxoacids contain at least one P=O unit and one P-OH group.

How many bridging oxygen atoms are present in P4O10?

1. 6
2. 4
3. 2
4. 5

Oxidation states of P in H4P2O5, H4P2O6, H4P2O7 are respectively

1. +3, +5, +4
2. +5, +3, +4
3. +5, +4, +3
4. +3, +4, +5

Zn gives H2 gas with H2SO4 and HCl but not with HNO3 because

1. Zn acts as oxidising agent when it reacts with HNO3
2. HNO3 is weaker acid than H2SO4 and HCl
3. In electrochemical series Zn is above hydrogen
4. NO3- is reduced in preference to hydronium ion.

Nitrogen forms N2, but phosphorus does not form P2, however, it exists as P4, reason is

1. triple bond present between phosphorus atoms
2. p - p bonding is weak
3. p - p bonding is strong
4. multiple bonds form easily.