Question

Show chemical equations involved and your step by step calculation to get full credit. Use the table provided to solve problems given below: Weak HCOOH H C2H:02 HNO2 HF NaHSO4 acid K. 1.8x10+ 1.8x105 4.5x104 7.2x104 1.2x102 HCIC H202 1.38x10- CH NH3 (CH3)2NH |CHÚNH |CH CH2NH3 |C HN Weak base Kb 1.8x10 4.27x100 5.4x104 4.4x10* 6.4x10+ 1.7x109 1. Write the dissociation of a common strong acid and a weak acid. 2. Write name of two polyprotic acids. 3. Show the dissociation of a typical weak base and identify conjugate acid and conjugate base. 4. How would you compare strength of equimolar weak bases? 5. Complete the following table. Show your work on a separate sheet. M, Compond [H] OH pH 0.25 M HF 0.50 M NH3 ? MNH 11.50 0.20 M MKF ? NHACI

Answer 1

E o [strong acid HCA (g) + Hole) * Hg * caq) + a cage] Lo Dissociation of a common strong acid strong acids are such acids which get virtually 100% dissociated. In above case He is a strong acid in aqueous medium. It completely dissociates into it and ct'. Ht later picked by Ho molecule to get Hot molecule. Tweak acid) . - Chacool (aq) + Hoces CH₂coo (aq) + H₂ot (aq) / acid 4 Partial dissociation of a common wook werk acids are such acids which get only dissociated. In above case, we take 0.01 m partially cho cook acid, dissociation of strong acids. I @ Polyprotic acids are such acids which have more than one ionizable protons in one molecule. . Ex O. A1507] is a diprotic acid with 2 lt ionizable ions. HSO4- H+ + SO2-

a triprotic acid with 3 ionizable Hit Ex 2. Apoy is ions. H₂PO - HPOR 4 4802 - H H+ + HT + + + H₂Porn HP Osta PO? 3. NHz (g) + Hoces = + NHI Taq) Conjugate acid Olta loq) Conjugate base 1 (weak-Base Base rud to Ex: gets protonated form Hat conjugate NH3 base acid. When it is removed from acid, it becomes conjugate base. Ex: ho acts as acid in above reaction. When H₂O remover let it gives Oh conjugate base . .. I 6. We assume MOH is a week base." Hence, it will not dissociate or react completely with H₂o. . MOH(aq) = m+ (aq) + Olt (aq). guitially: C . cx . co Egb ... G-ca where , c = concentration x= degree of in of Mol taken dissociation concentration of week base ca a change !

Ko is base ionization constant Ko = [M=Jeg [ort Jeq = cxxcd = cat Mon Jea (1-x) Ina since, we know x is small for week bases. Hence, we cou assume bax 1 .., K6= cx? where x = degree of dissociation Chore dissociation of base , more is its basicity, more will be its ② more will be its ko. Higher Hence, is the is Ko value, stronger the base. ок, (си, ни ) > К С И, NAJ .., CHgNha is stronger base than Colts NHA