Oxidation States of Lanthanides

Q. Which of the following molecular orbitals does not contain nodal plane?

1. $\pi 2p_x$
2. ${\sigma }^{\ast }2p_z$
3. $\sigma 1s$
4. ${\pi }^{\ast }2p_x$

Q. The third ionisation energy is maximum for: (A) Nitrogen (B) Phosphorus (C) Aluminium (D) Boron

Q.

Which of the following group 13 elements oxide is acidic in nature?

1. Tl₂O₃

2. Al₂O₃

3. B₂O₃

4. Ga₂O₃

Q. A compound of Xe and F is found to have 53.3% Xe (At.mass = 133) .oxidation number of Xe in this compound is ?

Q. 4. What is the covalency of B in [B(OH)4] with negative sign and its oxidation state.

Q. 2.why antiaromatic compounds are paramagnetic in nature ?

Q. 11. Due to metal deficiency defect, iron forms a non stoichiometric composition in which iron is present in +2 and +3 state. In this oxide 15percent iron is present in +3 oxidation state. The formula of oxide is

Q. Explain why is sodium less reactive than potassium.

Q. Consider the following ores.
Siderite, Iron Pyrites, Haematite, Malachite, Cuprite, Copper glance, Sphalerite, Calamine, Zincite.
Out of the above ores, $x$ is the number of ores in which oxidation number of metal is $1$. The value of $4x$ is:

Q. Which of the following shows highest oxidation number in combined state (1) Os (2) Ru (3) Both (1) and (2) (4) None

Q. The reason for the stability of $G{d}^{+3}$ ion is:

1. A half filled 4f subshell
2. A completely filled 4f subshell
3. It possesses the general electronic configuration of a noble gas
4. It has an empty 4f subshell

Q. What is the oxidation state of carbon and nitrogen in Cyanide and isocyanide

Q. 36.Oxidation number of K in KClO3

Q.

The oxidation number of Ca in Ca⁺² is

1. -1

2. -2

3. +1

4. +2

Q.

Among the following compounds the one that is paramagnetic is:

1. O₃

2. N₂O

3. O₂²

4. O₂^-

Q.

what is oxidation number of iodine in KI3 and carbons in CH3CH2OH

Q.

In Ni(CO)₄ the oxidation number of Ni is

a.2

b.0

c.4

d.8

Q. Most stable oxidation state of lanthanides is

1. 2
2. 3
3. 4
4. All of the above

Q.

Oxidation number of nickel in $Ni(CO{)}_4$

1. 0

2. +4

3. −4

4. +2

Q. When will the oxidation number be fractional? Also explain what is average oxidation number in this regard.

Q.

The oxidation state which is exhibited by boron is:

1. 4

2. 3

3. 1

4. 5

Q. Ferric iodide is very unstable but ferric chloride is a stable compound. This is because

1. hydration energy of ferric iodide is less than that of ferric chloride
2. $I^{-}$ ion is a stronger reducing agent as compared to $C{l}^{-}$ ion and thus, $F{e}^{3+}$ is easily reduced by $I^{-}$ ion to $F{e}^{2+}$ ion.
3. ferric iodide is a covalent compound whereas ferric chloride is ionic
4. ferric iodide is a covalent compound whereas ferric chloride is ionic

Q. 15. How does bond order and magnetic moment decrease in O_2- to O_2^{2-} and CO^+ to CO??

Q. The reason for the stability of Gd${}^3+$ ion is

1. 4 f sub shell empty
2. 4 f sub shell- completely filled
3. Possesses the general electronic configuration of noble gases
4. 4 f sub shell- half filled

Q.

What are the oxidation number of the underlined elements in each of the following and how do you rationalise your results?

(a) KI₃ (b) H₂S₄O₆ (c) Fe₃O₄ (d) CH₃CH₂OH (e) CH₃COOH

Q.

The element showing most stable +8 oxidation state in its compound is

1. Os

2. Ni

3. Re

4. Ru

Q.

Which of the alkali metal is having least melting point?

(a) Na (b) K (c) Rb (d) Cs

Q.

Why are Pt/Pd/Ni/Zn mostly used as catalysts?

Q. When will the oxidation number be fractional? Also explain what is average oxidation number in this regard.

Q.

Give reasons:-

(i) Lead(IV) chloride is highlt unstable towards heat.

(ii) Lead is known not to form iodide, PbI₄