231.
Which group contains coloured ions out of the following?
$$\eqalign{
& \left( {\text{i}} \right)C{u^ + } \cr
& \left( {{\text{ii}}} \right)T{i^{4 + }} \cr
& \left( {{\text{iii}}} \right)C{o^{2 + }} \cr
& \left( {{\text{iv}}} \right)F{e^{2 + }} \cr} $$
A
(i), (ii), (iii), (iv)
B
(iii), (iv)
C
(ii), (iii)
D
(i), (ii)
Answer :
(iii), (iv)
233. Among the following, the compound that is both paramagnetic and coloured, is
A
$$KMn{O_4}$$
B
$$Cu{F_2}$$
C
$${K_2}C{r_2}{O_7}$$
D
$${\text{All are coloured}}$$
Answer :
$$Cu{F_2}$$
234. Which of the following may be considered to be an organometallic compound?
A
\[\text{Nickel tetracarbonyl}\]
B
\[\text{Chlorophyll}\]
C
$${K_3}\left[ {Fe{{\left( {{C_2}{O_4}} \right)}_3}} \right]$$
D
$$\left[ {Co{{\left( {en} \right)}_3}} \right]C{l_3}$$
Answer :
\[\text{Chlorophyll}\]
235. Actinoids in general show more oxidation states than the lanthanoids. The main reason for this is
A
higher energy difference between $$5f$$ and $$6d$$ orbitals than between $$4f$$ and $$5d$$ orbitals
B
lower energy difference between $$5f$$ and $$6d$$ orbitals than between $$4f$$ and $$5d$$ orbitals
C
higher reactivity of actinoids than lanthanoids
D
actinoids are more basic than lanthanoids
Answer :
lower energy difference between $$5f$$ and $$6d$$ orbitals than between $$4f$$ and $$5d$$ orbitals
236. One mole of acidified $${K_2}C{r_2}{O_7}$$ on reaction with excess $$KI$$ will liberate ______ moles$$(s)$$ of $${I_2}.$$
A
3
B
1
C
7
D
2
Answer :
3
237. When $$KMn{O_4}$$ solution is added to oxalic acid solution, the decolourisation is slow in the beginning but becomes instantaneous after some time because
A
$$C{O_2}$$ is formed as the product
B
reaction is exothermic
C
$$MnO_4^ - $$ catalyses the reaction
D
$$M{n^{2 + }}$$ acts as autocatalyst
Answer :
$$M{n^{2 + }}$$ acts as autocatalyst
238. Which one of the following species is stable in aqueous solution ?
A
$$C{r^{2 + }}$$
B
$$MnO_4^{2 - }$$
C
$$MnO_4^{3 - }$$
D
$$C{u^ + }$$
Answer :
$$MnO_4^{2 - }$$
239.
In which of the following pairs are both the ions coloured in aqueous solution?
$$\left( {{\text{At}}{\text{. no}}{\text{.}}\,Sc = 21,Ti = 22,} \right.$$ $$\left. {Ni = 28,Cu = 29,Co = 27} \right)$$
A
$$N{i^{2 + }},T{i^{3 + }}$$
B
$$S{c^{3 + }},T{i^{3 + }}$$
C
$$S{c^{3 + }},C{o^{2 + }}$$
D
$$N{i^{2 + }},C{u^ + }$$
Answer :
$$N{i^{2 + }},T{i^{3 + }}$$
( 2 unpaired electrons) 240. The lanthanide contraction is responsible for the fact that
A
$$Zr$$ and $$Yt$$ have about the same radius
B
$$Zr$$ and $$Nb$$ have similar oxidation state
C
$$Zr$$ and $$Hf$$ have about the same radius
D
$$Zr$$ and $$Zn$$ have the same oxidation state
Answer :
$$Zr$$ and $$Hf$$ have about the same radius