Chemistry

Sphalerite is ore of zinc consists of ZnS during its concentration group 1 cyanides are used as depressants like NaCN

Major components of gun metal are Cu, Sn and Zn

$AgC\mathcal{l}+2N{H}_3\to \underset{\left(Solublecomplex\right)}{\left[Ag{\left(N{H}_3\right)}_2\right]C\mathcal{l}}$

Blue cupric metaborate is reduced to cuprous metaborate in a luminous flame.

$2Cu{\left(B{O}_2\right)}_2+2NaB{O}_2+C\underset{}{\overset{Luminous}{\to }}2CuB{O}_2+N{a}_2{B}_4{O}_7+CO$            

Cupric metaborate is obtained by heating boric anhydride & copper sulphate in a non-luminous flame as

$CuS{O}_4+B_2{O}_3\underset{}{\overset{Non-LuminiousFlame}{\to }}\underset{Blue}{Cu{\left(B{O}_2\right)}_2}+S{O}_3.$            

Al < Mg < Si < S < P

1^st I. E increase along period with exception on moving from group 2 to group 13 and group 15 to group 16

Size of hydrated ion $$ $\propto$ $\frac{1}{Ionicmobility}$ $\frac{}{}$

Size of hydrated ions $\propto \frac{1}{Ionicsize}$ $\frac{}{}$

Size of hydrated ions ;  $B{e}^{+2}>M{g}^{+2}>C{a}^{+2}>S{r}^{+2}$ ${}^{}{}^{}{}^{}{}^{}$

Ionic mobility ; $B{e}^{+2}<M{g}^{+2}<C{a}^{+2}<S{r}^{+2}$

Cu is the only element of 3d – series whose M²⁺ / M value is positive because of fact that low hydration enthalpy and high sublimation & ionization enthalpies.

Number of electrons in

$P{H}_3=15+3=18$  

$B_2{H}_6=5*2+6=16$  

$\begin{array}{l}CC{l}_4=6+17*4=6+68=74\\ N{H}_3=7+1*3=10\\ LiH=3+1=4\\ BC{l}_3=5+17*3=56\end{array}$  

$B_2{H}_6\&BC{l}_3$  are e^- deficient molecules. B₂H₆ is dimer of BH₃, both compound has 6e^- only.