24. Sodium bicarbonate can be used to remove grease and oil stains from clothing. What's the concentration of a sodium bicarbonate solution containing 2 moles NaHCO3 in
3 liters of solution?
a. 0.67 M
b. 1.5 M
C. 6 M
d. 56 M

(no3)⁻n has oxidation number x,o has oxidation number -2.(x*1 -2*3) charge of the nitrate ion, and we know that charge of the nitrate ion =-1.so,(x*1 -2*3) =-1x-6=-1x=+5answer a. +5.

Catalysts and intermediateshope i

According to arrhenius theory of acid and bases, an acid is a proton donor, while base donates hydroxyl ions. further, acid and base reacts to form salt and water.consider following example.hcl    +      h2o          →      cl-          +      h3o+here, hcl has donated a proton, hence it is an acid.now consider following reactionhcl      +      naoh            ↔      nacl      +        h2oin this reaction, hcl donates proton, hence it is acid. on other hand, naoh donates hydroxyl ion (i.e. hence it is a base.   

The answer is c.  na2haso4  and na2so4