Which of the following is true for the species $3{\mathrm{d}}^4$ configuration ?

(A) ${\mathrm{Cr}}^{2+}$ is reducing in nature                               

(B) ${\mathrm{Mn}}^{3+}$ is oxidising in nature.

(C) Both (A) and (B)                                             

(D) None of these

In which compound does vanadium have an oxidation number of +4?

(1) ${\mathrm{NH}}_4{\mathrm{VO}}_2$                                 

(2) ${\mathrm{K}}_4\left[\mathrm{V}{\left(\mathrm{CN}\right)}_6\right]$

(3) ${\mathrm{VSO}}_4$                                     

(4) ${\mathrm{VOSO}}_4$

 The increasing order of oxidising power among the following species is:

1. ${{}_{}}^{}$\(\mathrm{VO}_2^{+}<\mathrm{Cr}_2 \mathrm{O}_7^{2-}<\mathrm{MnO}_4^{-}\)   
2. \(\mathrm{VO}_2^{+}<\mathrm{MnO}_4^{-}<\mathrm{Cr}_2 \mathrm{O}_7^{2-}\)  
3. \(\mathrm{Cr}_2 \mathrm{O}_7^{2-}<\mathrm{VO}_2^{+}<\mathrm{MnO}_4^{-}\)
4. \(\mathrm{Cr}_2 \mathrm{O}_7{ }^{2-}<\mathrm{MnO}_4^{-}<\mathrm{VO}_2^{+}\)

Select the correct statement :

(A) ${\mathrm{PH}}_3$ reduces ${\mathrm{AgNO}}_3$ to metallic Ag.

(B) Organic tissues turn ${\mathrm{AgNO}}_3$ black by reducing it to Ag.

(C) $\mathrm{AgCN}$is soluble in $\mathrm{KCN}$.

(D) All are correct statements.

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

Which of the following ions has the most unpaired electrons?

What is the correct electronic configuration of Ti (Z = 22 atoms)?

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

The metal having different lattice from those of others is

(1) Co

(2) Fe

(3) Ag

(4) Ni

The correct order of E⁰(M²⁺/M) values with negative sign is : 

(1) Mn > Fe > Co > Cr

(2) Mn > Cr > Fe > Co

(3) Fe > Mn > Cr > Co

(4) Co > Fe > Mn > Cr