S E K O L A H M E N E N G A H A T A S B R A W I J A Y A S M A R T S C H O O LT e r a k r e d i t a s i “ A ”

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SALT HYDROLYSISA. Definition of Salt Hydrolysis

1. Pre Knowledge:No Question Answer1 What is a salt?

2 Mention kinds of salt!

3 Explain how to make a salt!

2. Properties of saltTo understanding the properties of salt, do this experiment!Title: Understanding properties of saltPurpose: explain properties of saltMaterial/apparatus!

Procedure:1. Drop the solution of each salt to palette about 3 drops2. Test by litmus and observe the color change of litmus3. Measure the pH of salt solution by universal indicatorObservation result

Question

Complete the following table

Conclusion

By Mr. Dasianto. dasianto@yahoo.co.id

3. Hydrolysis ReactionHydrolysis reaction is reaction that able to break down O – H bonding in water molecule. Not all salt able to break down this bonding. Complete the following tableNO Salt Parent base Parent acid Hydrolysis Reaction

1 NaClNaOH/Strong

baseHCl/strong acid

NaCl Na+ + Cl-

Na+ + H2O Cl - + H2O Not hydrolysis

2 K2SO4 ……………….. ……………

3 NH4Cl NH3/weak base HCl/strong acid

NH4Cl NH4+ + Cl-

NH4+ + H2O NH4OH + H+

Cl- + H2O Partially hydrolysis

4 BeSO4 ……………….. ……………

5 NaCNNaOH/strong

baseHCN/weak acid

NaCN Na+ + CN-

Na+ + H2O CN - + H2O HCN + OH-

Partially hydrolysis

6 CH3COOK ……………….. ……………

7 NH4CN NH3/weak base HCN/weak acid

NH4CN NH4+ + CN-

NH4+ + H2O NH4OH + H+

CN - + H2O HCN + OH-

Totally hydrolysis

8 HCOONH4 ……………….. ……………

Exercise

Identify properties of this salts and write the hydrolysis reaction of each saltNo Salt Properties Hydrolysis reaction1 KNO3

2 AlCl3

3 Mg(CN)2

4 K2C2O4

5 NaF

B. pH Calculation of SaltTo calculate pH of salt solution, we are need [OH-] or [H+]

ExerciseNo Question Answer

1 Calculate pH of:a. 100 mL NaF 0,1 M (Ka = 10-5)b. 100 mL NH4Cl 0,1 M (Kb = 10-5)c. 100 ml (NH4)2SO4 0,05 M (Kb = 10-5)d. 100 mL BaF2 0,05 M (Ka 10-5)

2 Calculate pH of:a. 100 mL NaOH 0,1 M mix with 100 mL HCN 0,1 M (Ka = 10-5)b. 200 mL HCN 0,1 M mix with 100 mL Ba(OH)2 0,1 M (Ka = 10-5)

Evaluation

1. The correct statement is ….a. CaS not hydrolyzed in waterb. K2SO4 partial hydrolyzed in waterc. Mg(HCOO)2 total hydrolyzed in waterd. (NH4)2S partial hydrolyzed in watere. NH4CN not hydrolyzed in water

2. The following mixture can be hydrolyzed in water, except ..a. 100 mL HCl 0,1 M with 50 mL NaOH 0,2 Mb. 100 mL HBr 0,1M with 100 NH4OH 0,1 Mc. 10 mL HCN 0,5 M with 50 mL KOH 0,1 M

d. 10 mL NH4OH 0,5 M with 10 mL HCl 0,1 Me. 10 mL CH3COOH 1 M with 100 mL NaOH 0,1 M

3. Larutan garam yang dapat mengubah warna kertas lakmus merah menjadi biru adalah…. a. NH4CN c. BaCl2 e. NaNO3

b. KF d. (NH4)2SO4

4. The solution that have highest pH is…. a. NH4NO3 0,1M d. CH3COOK 0,1Mb. KCl 0,1M e. NH4Cl 0,1Mc. K2SO4 0,1M

5. The pH value of 100 mL (CH3COO)2Ca 0,1 M.(Ka CH3COOH=10-5) is ….a. 5 c. 9 +log √2 e. 5 – log √5

b. 9 +log √5 d. 9

6. Hydrolysis constant (Kh) from 100 mL of NH4Br 0,1 M is….(Kb= 10-5)a. 10-8 c. 10-9 e. 2 x 10-9

d. 10-5 d. 2 x 10-5

7. A student dissolve 50 mL NaOH 0,2 M into 10 mL CH3COOH 1 M. (Ka CH3COOH=10-5). The pH of mixture after is added 40 mL water is….a. 10 c. 8,5 e. 9,5b. 8 d. 9

8. Mass of sodium acetate, CH3COONa must be added into 10 mL of water to give pH = 9 is .... (Ka = 10-5, Ar Al=26, Cl=35,5)a. 8,20 g c. 4,10 g e. 2,05 gb. 0,082 g d. 0,041 g

9. Diberikan data beberapa larutan garam berikut:1). NaF 0,1 M 4). NH4Cl 0,1 M2). K2SO4 0,1 M 5). Ca(CH3COO)2 0,1 M3). (NH4)CO3 0,1 M 6). (NH4)2SO4 0,1 MLarutan garam yang dapat mengubah warna kertas lakmus merah menjadi biru adalah…a. 1 dan 3 c. 4 dan 5 e. 1 dan 5b. 4 dan 6 d. 2 dan 4

10. Berdasarkan data pada soal nomor 9, garam yang mengalami hidrolisis sebagian adalah…a. 1, 2 dan 3 c. 3, 4 dan 5 e. 1, 4 dan 5

b. 3, 5 dan 6 d. 2, 4 dan 5

11. Campuran berikut yang dapat mengalami hidrolisis sebagian dan memiliki pH > 7 adalah…a. 100 mL HCl 0,1 M + 100 mL NH3 0,1 Mb. 200 mL NH3 0,2 M + 200 mL HF 0,2 Mc. 100 mL HF 0,2 M + 200 mL NaOH 0,2 Md. 50 mL H2SO4 0,2 M + 100 mL KOH 0,1 Me. 50 mL Ba(OH)2 0,2 M + 50 mL H2SO4 0,2 M

12. Sebanyak 100 mL NH4Cl 0,1 M (Kb = 10-5) memiliki pH sebesar…a. 4 c. 7 e. 10b. 5 d. 9

13. Sebanyak 250 mL Ba(CH3COO)2 0,1 M (Ka = 2 x 10-

5) memiliki pH sebesar…a. 5,5 – log √5 c. 7 e. 9b. 5 d. 8,5 + log√5

14. 100 mL NH3 0,1 M memiliki pH = 11. Maka pH

larutan 100 mL NH4Cl 0,1 M adalah…a. 3 c. 7 e. 11b. 5 d. 9

15. 150 mL of acetic acid (CH3COOH) 0,2 M (Ka = 10-5) react with 150 mL of potassium hydroxide (KOH) 0,2 M. pH of this mixture is…a. 5 c. 7 e. 9 b. 6-log 7 d. 8 + log 7

16. Hydrolysis equation for NH4Cl salt is….

a. NH4+ + H2O NH4OH + H+

Cl- + H2O HCl + OH-

b. NH4+ + H2O

Cl- + H2O HCl + OH-

c. NH4+ + H2O

Cl- + H2O d. NH4

+ + H2O NH4OH + H+

Cl- + H2O e. NH4

+ + H2O NH4OH + H+

2Cl- Cl2

17. Mass of ammonium sulfate, (NH4)2SO4, must be added into 100 mL of water to give pH = 5 is… (Kb = 10-5, Ar H = 1, N = 14, O = 16, S = 32)a. 0,33 g c. 1,32 g e.

13,2 gb. 0,66 g d. 2,64 g

18. Hydrolusis constant (Kh) from 100 mL of NaF 0,1 M is…(Ka = 4 x 10-7)a. 2 x 10-8 c. 5 x 10-5 e. 2,5 x

10-8

b. 2 x 10-8 d. 2,5 x 10-7

19. If each solution has the same volume, which have the higher pH?a. CH3COONa 0,1 M d. Na2SO4 0,1 Mb. KCl 0,1 M e. CH3COONH4 0,1 Mc. NH4Cl 0,1 M

20. According to the data in table below, the incorrect

statement is ….No

Kinds Salt

a Not hydrolysis CaCl2b Not hydrolysis K2SO4

c Partial hydrolysis MgBr2

d Partial hydrolysis (NH4)2Se Total hydrolysis NH4CN

21. The following mixture that can be hydrolyzed, except ....a. 100 mL HBr 0,1 M with 50 mL KOH 0,2 Mb. 100 mL HCOOH 0,1M with 50 NH4OH 0,2Mc. 10 mL CH3COOH 0,5 M with 50 mL KOH 0,1 Md. 10 mL NH4OH 0,5 M with 50 mL HCl 0,1 Me. 10 mL HCN 1 M with 100 mL NaOH 0,1 M

22. The following salts that have alkaline properties is....a. MgCl2 d. CH3COOKb. Na2SO4 e. NH4CNc. NH4NO3

23. What is the pH of 10 mL (NH4)2SO4 0,1 M, if Kb NH4OH = 2 x 10-5 ?

a. 3 b. 5 c. 9 d. 11 e. 13

24. One hundred mililiters of acetic acid , CH3COOH 0,2 M (Ka=10-5) react with 100 mL sodium hydroxide, NaOH 0,2M. pH of mixture is ....

a. 3 b. 5 c. 9 d. 11 e. 13

25. Mass of ammonium nitrate, NH4NO3 must be added into 250 mL of water to give pH = 5 is .... (Kb = 2x10-5, Ar H=1, N= 14, O=16)

a. 0,4 g c. 10 g e. 1 g b. 5 g d. 4 g

DAFTAR PUSTAKABrady. 2006. General chemistry. London: LongmanEffendy. 2007. A-Level Chemistry 2B. Malang:Bayu Media.Utami, 2009. KIMIA XI. BSE DEPDIKNASRatcliff, dkk. 2006. CGE PROBLEM: Cambridge pressHariyanto. 2010. Salt Hydrolysis. Worksheet at SMAN 3 Malang.Arsip Soal Pribadi