D & F Block Elements MCQs for NEET — Chemistry Questions with Answers

(a) Wilkinson's catalyst is $\left[\mathrm{RhCl}\right({\mathrm{PPh}}_3{)}_3]$, Red-violet in colour and has square planar structure. It is used for selective hydrogenation of organic molecules at room temperature and pressure.

${\mathrm{TiCl}}_4+({\mathrm{C}}_2{\mathrm{H}}_5{)}_3\mathrm{Al}$ is Zeigler Natta catalyst.

$({\mathrm{C}}_2{\mathrm{H}}_5{)}_4\mathrm{Pb}$ is an anti-knocking agent.

cis-platin is used as an anti-cancer agent.

(b) 

$$\begin{gathered} \underset{\mathrm{Acid}}{\mathrm{Zn}(\mathrm{OH}{)}_2}+\underset{\mathrm{Base}}{2{\mathrm{OH}}^{-}}\underset{}{\to } \underset{\mathrm{Salt}}{{\mathrm{ZnO}}_2^{2-}}+\underset{\mathrm{water}}{2{\mathrm{H}}_2\mathrm{O}} \\ \underset{\mathrm{Base}}{\mathrm{Zn}(\mathrm{OH}{)}_2}+2{\mathrm{H}}^{+}\to \underset{\mathrm{Salt}}{{\mathrm{Zn}}^{2+}}+\underset{\mathrm{water}}{2{\mathrm{H}}_2\mathrm{O}} \end{gathered}$$

(b) Interstitial compound ${\mathrm{Fe}}_3{\mathrm{C}}_{}$ (cementide) is formed.

(b) ${\mathrm{Na}}_2\left[\stackrel{\mathrm{II}}{\mathrm{Fe}}\right(\mathrm{NO}\left)\right(\mathrm{CN}{)}_2] + {\mathrm{Na}}_2\mathrm{S} \stackrel{}{\to }{\mathrm{Na}}_4[\stackrel{\mathrm{II}}{\mathrm{Fe}}\left(\mathrm{CN}{)}_5\right(\mathrm{NOS}\left)\right]$

(c) $\underset{\mathrm{X}}{2{\mathrm{MnO}}_2}+ 2{\mathrm{K}}_2{\mathrm{CO}}_3+\underset{\left(\mathrm{air}\right)}{{\mathrm{O}}_2}\stackrel{∆}{\to } \underset{\underset{\left(\mathrm{Y}\right)}{\mathrm{green}}}{2{\mathrm{K}}_2{\mathrm{MnO}}_4}+2{\mathrm{CO}}_2$

$\underset{\mathrm{Y}}{2{\mathrm{K}}_2{\mathrm{MnO}}_4}+{\mathrm{Cl}}_2\stackrel{}{\to } \underset{\left(\mathrm{Z}\right) \mathrm{Pink}}{2{\mathrm{KMnO}}_4}+2\mathrm{KCl}$

(c) $\mathrm{Cu}(\mathrm{CN}{)}_2$ and ${\mathrm{CuI}}_2$ being unstable spontaneously decomposes into $\mathrm{CuCN}\downarrow$ and $\mathrm{CuI}\downarrow$ respectively at room temperature.

(d) Practically ${\mathrm{F}}^{-}$ ion being very weak R.A. has no reducing property.

(b) $$\begin{gathered} \mathrm{NaCl}\left(\mathrm{s}\right)+{\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7\left(\mathrm{s}\right)+{\mathrm{H}}_2{\mathrm{SO}}_4(\mathrm{few} \mathrm{drops})\underset{\mathrm{reaction}}{\overset{\mathrm{Non} \mathrm{redox}}{\to }} \underset{\mathrm{orange} \mathrm{red} \mathrm{vapours}}{{\mathrm{CrO}}_2{\mathrm{Cl}}_2}\uparrow +\mathrm{HO} \\ {\mathrm{CrO}}_2{\mathrm{Cl}}_2+{\mathrm{OH}}^{-}\left(\mathrm{aq}\right)\to \underset{\mathrm{yellow} \mathrm{solution}}{{\mathrm{CrO}}_4^{2-}}+{\mathrm{Cl}}^{-}+2{\mathrm{H}}_2\mathrm{O} \end{gathered}$$

(D)

     (A) Higher the number of unpaired electrons higher will be the strength of metallic bonds. Hence

          transition elements have higher enthalpies of atomization.

     (B) In Cr the second electrons has to be removed from stable half filled electron configuration i.e. $3{\mathrm{d}}^5.$

           In Cu the second electron has to be removed from stable completely filled electron configuration i.e. $3{\mathrm{d}}^{10}.$

     (C) The sum of ${\mathrm{IE}}_1 \mathrm{and} {\mathrm{IE}}_2$ of Ni is less than that of Pt whereas the sum of ${\mathrm{IE}}_1, {\mathrm{IE}}_2, {\mathrm{IE}}_3 \mathrm{and} {\mathrm{IE}}_4$ are

           reversed.

     (D) Occurs in the middle, e.g., manganese has +7 oxidation state.