Question dos5. Dissociation constant of NHcuatroOH is step one.8 x 10 -5 the hydrolysis constant of NH4Cl would be …….. Murrieta escort reviews…….. (a) 1.8 x 10 -19 (b) 5.55 x 10 -10 (c) 5.55 x 10 -5 (d) 1.80 x 10 -5 Answer: (b) 5.55 x 10 10
- Lewis acidic try a kinds one allows an electron couple.
- Lewis acidic are an optimistic ion (or) an enthusiastic electron lacking molecule.
- Example, Fe 2+ , CO2, BFstep three, SiF4 etc…
- Lewis legs try a types one donates an enthusiastic electron partners.
- Lewis foot was an anion (or) basic molecule which have atleast one to lone set of electrons.
- Example, NH3, F – , CH2 = CH2, CaO etc….
Question 2. Discuss the Lowry – Bronsted concept of acids and bases. Answer: According to Lowry – Bronsted concept, an acid is defined as a substance that has a tendency to donate a proton to another substance and base is a substance that has a tendency to accept a proton from other substance. When hydrogen chloride is dissolved in water, it donates a proton to the later. Thus, HCl behaves as an acid and H2O is base. The proton transfer from the acid to base can be represented as HCl + H2O \(\rightleftharpoons\) H3O + + Cl –
When ammonia is dissolved in water, it accepts a proton from water. In. this case, ammonia (NH3) acts as a base and H2O is acid. The reaction is represented as H2O + NH3 \(\rightleftharpoons\) NH4 + + OH – Let us consider the reverse reaction in the following equilibrium
H3O + donates a proton to Cl – to form HCI i.e., the products also behave as acid and base. In general, Lowry – Bronsted (acid – base) reaction is represented as Acid1 + Base2 \(\rightleftharpoons\) Acid2 + Base1 The species that remains after the donation of a proton is a base (Base1)and is called the conjugate base of the Bronsted acid (Acid1). Conjugate acid – base pair
HCl and Cl – , H2O and H3O are two conjugate acid – base pairs. i.e., Cl– is the conjugate base of the acid HCl (or) HCl is conjugate acid of Cl – Similarly H32O. Limitations of Lowry – Bronsted theory. Substances like BF3 , AICl3 etc., that do not donate protons are known to behave as acids.
- HS – (aq) + HF \(\rightleftharpoons\) F – (aq) + H2S (aq)
- HPO4 2- + SO3 2- \(\rightleftharpoons\) PO4 3- + HSO3 –
- NH4 + + CO3 2- \(\rightleftharpoons\) NH3 + HCO3 –
O is the conjugate acidic away from H
• HF and F – , HS – and H2S are two conjugate acid – base pairs. • F – is the conjugate base of the acid HF (or) HF is the conjugate acid of F – • H2S is the conjugate acid of HS – (or) HS – is the conjugate base of H2S.
This means, chemical substances types that disagree just of the an effective proton are known as conjugate acidic – base sets
• HPO4 2- and PO4 3- , SO3 2- and HSO3 – are two conjugate acid – base pairs. .PO4 3- is the conjugate base of the acid HPO4 2- (or) HPO4 2- is the conjugate acid of PO4. •HSO3 – is the conjugate acid of SO3 2- (or) SO3 2- is the conjugate base of HSO3 – .
• NH + and NH3, CO3 2- and HCO3 – are two conjugate acid-base pairs. • HCO3 – is the conjugate of acid CO3 2- (or) CO3 2- is the conjugate bases of HCO3 – . • NH3 is the conjugate base of NH4 + (or) NH4 + is the conjugate acid of NH3.