answer : the correct answer is 2) hno₃ and naoh .
arrhenius concept of acid and base :
acid :
according to arrhenius acid are those which release h⁺ or hydronium ion (h₃o⁺) in aqueous solution .
example : hcl +h₂o ↔ h₃o⁺ + cl⁻
hcl is giving h₃o⁺ ion in water , hence it is an arrhenius acid .
base :
according to arrhenius , bases are those which releases oh⁻ ions in aqueous solution .
example : koh (aq) ↔ k⁺ + oh⁻
since koh is producing oh⁻ ions hence , it is an arrhenius base .
checking the options :
1) ch₃oh and naoh :
ch₃oh is known as methanol , an organic compound , which is neutral compound . the dissociation of ch₃oh is negligible . it is very very weak acid (ka = 3.2 * 10 ⁻¹² ) .
naoh being ionic gives na⁺ and oh⁻ ions in aqueous solution as :
naoh ↔ na⁺ + oh⁻ . hence it is an arrhenius base
it can be concluded that ch₃oh and naoh is not arrhenius acid and base.
2) hno₃ and naoh :
hno₃ is an ionic compound which gives ions h⁺ and no₃⁻ ion in aqueous solution as:
hno₃ + h₂o ↔ h₃o⁺ + no₃⁻
since it is giving h⁺ ion . hno₃ is arrhenius acid .
naoh being ionic gives na⁺ and oh⁻ ions in aqueous solution as :
naoh ↔ na⁺ + oh⁻
. hence it is an arrhenius base .
it can be said that hno₃ and naoh are arrhenius acid and base.
3) ch₃oh and hcl
as discussed ch₃oh is neutral compound .
while hcl in aqueous solution dissociates to give h⁺ and cl⁻ ions as :
hcl + h₂o→ h₃o⁺ + cl⁻ . so hcl is arrhenius acid .
hence , ch₃oh and hcl are not arrhenius acid and base.
4) hno₃ and hcl :
hno₃ as discussed gives h⁺ in aqueous solution , while hcl also gives h⁺ in aqueous solution .
hence both hno₃ and hcl are arrhenius acid they are not acid and base .
so the arrhenius acid and base are 2) hno₃ and naoh.
