Question

7) For the chemical reaction NH3(aq) + HCl(aq) + NH4" (aq) + Cl(aq) the acid and conjugate base are a) NH; (acid); C (conjugate base) b) NH; (acid); NH4 (conjugate base) c) HCI (acid); Cl"(conjugate base) d) HCI (acid): NH (conjugate base) e) HCI (acid); NHA (conjugate base) 8) A buffer solution is formed by adding 0.0100 moles of potassium dihydrogen phosphate (KH_PO4) and 0.0100 moles of potassium hydrogen phosphate (K,HPO) into 1.000 liters of water. When 0.0010 moles of NaOH is added to this solution, what will happen? a) The pH of the solution will decreases by a large amount ( > 0.10 pH units) b) The pH of the solution will decreases by a small amount (< 0.10 pH units) c) The pH of the solution will be exactly the same as before the addition of the NaOH d) The pH of the solution will increases by a small amount (<0.10 pH units) c) The pH of the solution will increases by a large amount (> 0.10 pH units) 9) For which of the following substances does phosphorus (P) have the largest value for oxidation number? a)P b) PO, c) H PO d) Na P e) PF

Answer 1

Ans7 NH3(aq) + Halog) 'N Hytlagt el caq) as it donates The acid Ht and here is he co the conjugate base formed is So, the answer is Hal Carid, co- (conjugate bases KH₂ Pou and KahPou buff on is PH given as pH = pka (KH₂ Pow) tlogo [Ka Hlo) IK H2 Poy

is Ma. Soinita ph given. 2.), '. phinital pha (KHz Pow) + + lagi..al PHU =pka (KHapou Now, ifo.ool mole added, of NaOH 2 H₂ Pou + NaOH Initial moles o, o) 0,ool 10 HPO 2- Ol009. o.oll sas pHfinal = p Kacho KH2PO4) +D og in locul) 10.009 Soe (0.01) SpH = pka LH2PO4) tlagio tort) 0.009 — рка (нароч). +0,037 12 So, and were d) The pH of the solh will by a small amount koo10 units). increase

Ang- Pu o oxidation state RO3² +3 oxidation state H3PO4 +5 oxidation state Nasl -3 oxidation state PF3 +3 oxidation state So, the answer is . © H3 Poy. 3.