From the following, which is the most basic hydroxide?
1. Ce(OH)3
2. Lu(OH)3
3. Yb(OH)3
4. Tb(OH)3
The reason for lanthanoid contraction is:
1. Negligible screening effect of 'f' orbitals
2. Increasing nuclear charge
3. Decreasing nuclear charge
4. Decreasing screening effect
A diamagnetic lanthanoid ion among the following is :
(At. numbers: Ce = 58, Sm = 62, Eu = 63, Yb = 70)
1. Ce2+
2. Eu2+
3. Sm2+
4. Yb2+
Among the following, the incorrect statement regarding interstitial compounds is:
1. They retain metallic conductivity.
2. They are chemically reactive.
3. They are much harder than the pure metal.
4. They have higher melting points than the pure metal.
A pair among the following that have the same size is:
1. Fe2+, Ni2+
2. Zr4+, Ti4+
3. Zr4+ , Hf4+
4. Zn2+, Hf4+
Which of the following species is colourless?
1. and
2. Cu2Cl2 and
3. and Cu2Cl2
4. and
Actinide contraction is
mainly related to:
1. Poor shielding by 5f subshell
2. Extraordinary decrement in Zeff
3. Both (1) and (2)
4. Strong shielding by 5f subshel
CrO42- (yellow) changes to Cr2O72- (orange) in pH = x and vice versa in pH = y.
The value of x and y will be:
1. 6, and 8
2. 6, and 5
3. 8, and 6
4. 7, and 7
When iron becomes passive by "X", it is due to the formation of "Y". X and Y, respectively, are:
1. Dil. HCl,
2. 80% Conc. ,
3. Conc. ,
4. Conc. HCl,
When KMnO4 solution is added to hot oxalic acid solution, the decolorization is slow in the beginning but becomes instantaneous after some time. This is because :
1. acts as auto catalyst.
2. is formed.
3. Reaction is exothermic.
4. catalyses the reaction.