The radius of La³⁺ (atomic number of La=57) is 1.06 $\stackrel{o}{A}$. Which one of the following given values will be closest to the radius of Lu³⁺ (atomic number of Lu =71)

(1) 1.60 $\stackrel{o}{A}$

(2) 1.40 $\stackrel{o}{A}$

(3)1.96 $\stackrel{o}{A}$

(4)0.85 $\stackrel{o}{A}$

Match the underlined atom in Column A with oxidation number in Column B.

                    A                                                          B

(a)  [Fe(CN)₅$\stackrel{\oplus }{N}$O]^2-                                                0(I)

(b)  [Ag(CN)₂]^-                                                      3(II)

(c)  [Cr(en)₃]³⁺                                                      1(III)

(d)  Ni(CO)₄                                                          2(IV)

              a         b        c       d

(A)         I         II       III      IV

(B)        II        III       IV       I

(C)       IV        III       II        I

(D)       II        III        I        IV

By calculating E^o value of the following reaction,which one of the following reaction are spontaneous.

Given 

$E_{C{u}^{2+}/Cu}^o=0.34 V,E_{Z{n}^{2+}/Zn}^o=-0.76 V, E_{A{g}^{+}/Ag}^o=0.80 V.$
$\left(a\right) 2Ag +Z{n}^{2+}\to 2A{g}^{+}+Zn$
$\left(b\right)Cu +Z{n}^{2+}\to Zn +C{u}^{2+}$
$\left(c\right) Zn +C{u}^{2+}\to Z{n}^{2+}+Cu$
$\left(d\right) 2A{g}^{+}+Cu \to 2Ag+C{u}^{2+}$

(A) Only d

(B) Only b

(C) Both c & d

(D) Both a & c

Which of the following species has the highest number of unpaired electrons?

1. Fe²⁺

2. Fe³⁺

3. Co³⁺

4. Co²⁺

The atomc number of potassium is 19 & that of manganese is 25. Although the colour of MnO₄^- is dark violet yet the K⁺ is colourless.This is due to the fact that

(1) Mn is a transition element; while K⁺ is not

(2) [MnO₄]^- is negatively charged; while K⁺ has a positive charge.

(3) The effective atomic number of Mn in [MnO₄]^- is 26; while for K⁺ , the atomic number s 18

(4) The Mn in a high positive oxidation state allow charge transfer transitions.

Heating of Ag with dil. HNO₃ give

1. NO

2. NO₂

3. N₂O

4. N₂O₃

Zinc dissolve in an excess of NaOH because of the formation of:

1. ZnO

2. Zn(OH)₂

3. NaZn(OH)₃

4. Na₂ZnO₂

When excess of SnCl₂ is added to HgCl₂, the substance formed is

1. Hg₂Cl₂

2. Sn

3. Hg

4. Cl₂

The oxidation number is changed in which of the following case

1. SO₂ gas is passed into $C{r}_2{O}_7^{2-}/H^{+}$

2. Aqueous solution of $Cr{O}_4^{2-}$ is acidified

3. $Cr{O}_{2}C{l}_2$ is dissolved in NaOH

4. $C{r}_2{O}_7^{2-}$ solution is made alkaline

Which of the following elements form stable dinuclear ions

1. Zn

2. Cd

3. Hg

4. Fe