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Can you please solve this question with all parts. Thank You. Step by step solut

ID: 521566 • Letter: C

Question

Can you please solve this question with all parts. Thank You. Step by step solution

A 50 mL of water requires 12 mL of 0.02-N H_2SO_4 to titrate it to the phenolphthalein end point and require 16mL of 0.02-N H_2SO_4 to titrate it further to the methyl-orange endpoint. What is the bicarbonate alkalinity in mg/L as CaCO_3? What is the carbonate alkalinity in mg Las CaCO_3? What is the total alkalinity in mg/L as CaCO_3? What is (are) the major alkalinity species and its (their) concentration(s) in meq/L? What is (are) the major acidity species and its (their) concentration(s) in meq/L?

Explanation / Answer

Here, P=12 and M=16

Condition : P > ½ M, Sample contains OH- and CO32- only.

1) So, the bicarbonate alkalinity is 0 mg/L, since the sample contains only OH- and CO32-.

2) For carbonate alkalinity, the formula is 2[M-P].

=2[16-12] = 8ml.

V1= Vol. of acid= 8ml

V2= Vol. of water sample= 50ml

N1= Normality of acid= 0.02 N

N2= Normality of water= ?

N2 = V1N1/V2 = (8*0.02)/50 = 0.0032 N

Amount of Carbonate alkalinity in terms of CaCO3= N2* Eq. weight of CaCO3 = 0.0032*50 gms = 0.0032*50*1000 mg/L = 160 mg/L

3) Total alkalinity= OH- and CO32- alkalinity

OH- alkalinity=

2P-M = 2*12-16 = 8 ml

For, OH- alkalinity also, N2 = 0.0032N

So, Amount of OH- alkalinity in terms of CaCO3= N2* Eq. weight of CaCO3 = 0.0032*50 gms = 0.0032*50*1000 mg/L = 160 mg/L

So, total Alkalinity= 160+160 mg/L= 320 mg/L

4) Major alkalinity species are OH- and CO32- . Their concentrations are 3.2 meq/L and 3.2 meq/L respectively.