Chemistry

${\left(N{H}_4\right)}_{2}C{r}_2{O}_7\underset{}{\overset{\Delta }{\to }}\boxed{N_2}+C{r}_2{O}_3+4H_{2}O$

$KMn{O}_4+HC\mathcal{l}\to MnC{\mathcal{l}}_2+KC\mathcal{l}+\boxed{C{\mathcal{l}}_2}+H_{2}O$

$A\mathcal{l}+NaOH+H_{2}O\to Na\left[A\mathcal{l}{\left(OH\right)}_4\right]+\boxed{H_2}$

$NaN{O}_3\to NaN{O}_2+\boxed{O_2}$

Following are the $\Delta H°$  hydration of given ions

Cr²⁺ - 1926 KJ/mole

Mn²⁺ - 1860 KJ/mole

Fe²⁺ - 2000 KJ/mole

Co²⁺ - 2078 KJ/mole

(a) low solubility of LiF in H₂O due to high lattice energy.

(b) $O_2^{-}$  has unpaired e^- thus paramagnetic.

(c) Na in liq NH₃ forms electronated ammonia thus conducting in nature.

(d) $d_K<d_{Na}$ .

Cobalt (II) meta borate is a blue colour of Bead.

In clark's method Ca (OH)₂ is used for softening hard water.

$Ca{\left(HC{O}_3\right)}_2+Ca{\left(OH\right)}_2\to 2CaC{O}_3+2H_{2}O$

$Mg{\left(HC{O}_3\right)}_2+2Ca{\left(OH\right)}_2\to 2CaC{O}_3+Mg{\left(OH\right)}_{2}2H_{2}O$    

Thus CaCO₃ and Mg (OH)₂ are formed in reaction.

Here 'X' is the Gypsum (CaSO₄.2H₂O) which is used to enhance the setting of time

In leaching suitable compound is used as solvent.

$A{\mathcal{l}}_2{O}_3+2NaOH+3H_{2}O\to 2Na\left[A\mathcal{l}{\left(OH\right)}_4\right]$

Stannane is the tetrahedral shape of molecule.

Hybridisation is- sp³, shape and structure are tetrahedral

Liquation refining process is applicable for the metal having low m.p, but containing impurities have higher m.p

The difference in boiling or melting point, even after nearly the same molecular geometry, is because opf the presence of hydrogen bond. HF forms intermolecular hydrogen bonds due to fluorine's high electronegativity. This intermolecular hydrogen bonding requires more energy due to break the hydrogen bonds and melt or boil. So, stronger intermolecular forces of HF result in a higher boiling point.