Chemistry Questions

Silver nitrate is the basic substance from which silver bromide is obtained. The photographic films are impregnated with the light sensitive AgBr.

Hybridisation of Ni is e-  

Unpaired 3d8in  is 2 

So $$\begin{gathered} Ω = n(n+2)BM \\ =2x4 = 8 = 2.82BM \end{gathered}$$

The order of basicity in ammonia is different in gaseous phases vs. aqueous phases due to hydrogen bonding.

So in gaseous phases it's the well known: 3' > 2' > 1'> NH3. Just so we're on the same page, this is due to the inductive effect of electron donating alkyl groups--they destabilize the lone pair on nitrogen atom, making nitrogen more basic.

But in aqueous phase, the order is slightly different: 2'> 1'> 3' > NH3.

Removing the contaminents if any in the water which causes harm to our health is involved in the purifying of water. 

This process involves chemicals. Chloramines, Hydrogen peroxide, Iodine are the chemicals which are used in purifying water.

Gammaxene, D.D.T. & Bleaching powder are important compounds of Chlorine.