Which of the following has maximum 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

The correct electronic configuration of Ti(Z=22 atom) is

(1) $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^2$

(2) $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{2}4p^6$

(3) $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^4$

(4) $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^2$

Of the ions, Zn²⁺, Ni²⁺and Cr³⁺(atomic number of Zn =30, Ni=28 and Cr=24).

(1) Only Zn²⁺ is Colourless and  Ni²⁺and Cr³⁺ are coloured

(2) All these are colourless

(3) All these are coloured

(4) Only Ni²⁺ is coloured and Zn²⁺ and Cr³⁺ are colourless.

Which is not true in case of transition metals

(1) They are malleable and ductile

(2) They have high melting and boiling points

(3) They crystallise with body centered cubic and hexagonal close packed structure only

(4) They show variable oxidation states although not always