Assertion: To a solution of potassium chromate if a strong acid is added it changes its colour from yellow to orange.

Reason : The colour change is due to the oxidation of potassium chromate.

1. If both the assertion and the reason are true and the reason is a correct explanation of the assertion
2. If both the assertion and reason are true but the reason is not a correct explanation of the assertion
3. If the assertion is true but the reason is false
4. If both the assertion and reason are false

Which one of the following statements is not correct

1. Nickel forms Ni(CO)₄

2. All the transition metals form mono-metallic carbonyls

3. Carbonyl are formed by transition metals

4. Transition metals form complexes

Which of the following pairs of compounds are more stable

(A) $K_2\left[NiC{l}_6\right],\left[Pt\right(CN{)}_4{]}^{2-}$

(B) NiCl₄, PtCl₄

(C) $\left[Ni\right(CN{)}_4{]}^{2-}, K_2\left[Pt\right(C{l}_6\left)\right]$

(D) PtCl₂, NiCl₂

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