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Grade 11 Chemistry Effective Homework 5: Salt Hydrolysis | Brief Solutions
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1 Choose the alkaline salt solution. Show answer
2 Which ion undergoes hydrolysis? Show answer
3 Which salt is acidic without hydrolysis? Show answer
4 General properties of salt hydrolysis: choose incorrect statements. Show answer
5 Choose correct ionic equations that represent salt hydrolysis. Show answer
6 Which action suppresses water ionization? Show answer
7 Effects of ammonia, acid salt, sodium acetate and heating on water ionization. Show answer
8 Which addition cannot make the ammonium-to-chloride ratio in NH4Cl approach $1:1$? Show answer
9 Which additions can make the concentration ratio exactly $1:1$? Show answer
10 Ammonium chloride hydrolysis in heavy water: choose correct statements. Show answer
11 Which equimolar ammonium salt has the greatest ammonium-ion concentration? Show answer
12 Compare pH of sodium acetate, carbonate and silicate from acid strengths. Show answer
13 Which listed equimolar carbonate or sulfite salt gives the greatest water ionization? Show answer
14 The water-derived hydroxide ratio in HCl and NaX is $10^{-9}$. Find NaX pH. Show answer
15 Choose an experiment showing that sodium-acetate hydrolysis is endothermic. Show answer
16.1 Write AlCl3 hydrolysis. Show answer
$\mathrm{Al^{3+}+3H_2O\rightleftharpoons Al(OH)_3+3H^+}$
16.2 Write NaF hydrolysis. Show answer
$\mathrm{F^-+H_2O\rightleftharpoons HF+OH^-}$
16.3 Write NaClO hydrolysis. Show answer
$\mathrm{ClO^-+H_2O\rightleftharpoons HClO+OH^-}$
16.4 Write CuSO4 hydrolysis. Show answer
$\mathrm{Cu^{2+}+2H_2O\rightleftharpoons Cu(OH)_2+2H^+}$
16.5 Write stepwise Na2S hydrolysis. Show answer
$\mathrm{S^{2-}+H_2O\rightleftharpoons HS^-+OH^-}$;$\mathrm{HS^-+H_2O\rightleftharpoons H_2S+OH^-}$
17.1 Why is sodium-acetate solution with phenolphthalein faint red? Show answer
$\mathrm{CH_3COO^-+H_2O\rightleftharpoons CH_3COOH+OH^-}$ produces an alkaline solution.
17.2 Quicklime and ammonium-nitrate baths deepen and lighten the red color, respectively. Choose the correct heat-effect statements. Show answer
17.3 Add HCl, NaOH, Na2CO3 and FeSO4 separately to sodium acetate. Give hydrolysis-shift directions. Show answer
Right, left, left, right.
18.1 Acidity and hydrolysis equation of NH4Cl. Show answer
Acidic; $\mathrm{NH_4^++H_2O\rightleftharpoons NH_3\cdot H_2O+H^+}$.
18.2 Find pH of $0.18$ mol/L NH4Cl with $K_b=1.7\times10^{-5}$. Show answer
18.3 Write NH4HSO4 dissociation and its reaction with a small amount of NaOH. Show answer
$\mathrm{NH_4HSO_4\to NH_4^++H^++SO_4^{2-}}$;$\mathrm{H^++OH^-\to H_2O}$
18.4 Degree of ammonium hydrolysis in $0.1$ mol/L NH4HSO4. Show answer
18.5 Which listed ammonium salt has the greatest total salt concentration at equal pH? Show answer
18.6 From carbonic-acid pKa1 $6.3$, find hydrogen-carbonate hydrolysis constant. Show answer
$K_h=10^{-7.7}\approx2.0\times10^{-8}$
18.7 Explain why ammonium fertilizer should not be mixed with plant ash. Show answer
$\mathrm{CO_3^{2-}+H_2O\rightleftharpoons HCO_3^-+OH^-}$ and $\mathrm{NH_4^++OH^-\rightleftharpoons NH_3\cdot H_2O}$. Alkalinity promotes ammonia formation and volatilization, causing nitrogen loss.
18.8a Use equilibrium constants to explain why NH4HCO3 is alkaline. Show answer
$K_h(\mathrm{HCO_3^-})\approx2.0\times10^{-8}$ exceeds $K_h(\mathrm{NH_4^+})\approx5.88\times10^{-10}$, so the basic effect dominates.
18.8b How does $c(\mathrm{NH_3\cdot H_2O})/c(\mathrm{H_2CO_3})$ change on dilution in the usual weak-salt approximation? Show answer
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