NaClO를 2.0 L 물에 녹였더니 pH가 10.50

NaClO를 2.0 L 물에 녹였더니 pH가 10.50

 

 

고체 NaClO를 2.0 L 물에 녹였더니 pH가 10.50이었다.

물에 녹은 NaClO의 양은 얼마인가?

단, HClO의 Ka = 3.0×10^(-8).

 

 

A solution is made by adding solid sodium hypochlorite, NaClO, to enough water to make 2.00 L of solution. If the solution has a pH of 10.50, how many moles of NaClO were added to the water?

 

 

A solution of pH = 10.50 is made by adding solid sodium hypochlorite (NaClO) to enough water to make 2.00 L of solution. How many moles of NaClO were added? The Kb of the ClO^- anion is 3.3×10^(-7).

 

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가용성염의 100% 이온화

NaClO(aq) → Na^+(aq) + ClO^-(aq)

 

 

 

약산의 짝염기의 가수분해(평형)

( 참고 https://ywpop.tistory.com/5502 )

 

ClO^-(aq) + H2O(l) ⇌ HClO(aq) + OH^-(aq)

 

Kb = x^2 / C-x

( 참고 https://ywpop.tistory.com/4294 )

 

 

 

Kh = Kb = Kw / Ka

( 참고 https://ywpop.tistory.com/2937 )

 

= (1.0×10^(-14)) / (3.0×10^(-8))

= 3.3×10^(-7)

 

 

 

pOH = 14.00 – pH

= 14.00 - 10.50

= 3.50

 

 

 

pOH = -log[OH^-] = 3.50

[OH^-] = 10^(-3.50) M = x

 

 

 

Kb = x^2 / C-x

 

C = (x^2 / Kb) + x

= [(10^(-3.50))^2 / (3.3×10^(-7))] + (10^(-3.50))

= 0.3033 M

---> NaClO 용액의 몰농도

 

 

 

(0.3033 mol/L) (2.0 L) = 0.6066 mol NaClO

= 0.61 mol NaClO

 

 

 

NaClO의 몰질량 = 74.44 g/mol

(0.6066 mol) (74.44 g/mol) = 45.2 g NaClO

 

 

 

 

[키워드] NaClO 2.0 L pH 10.50 HClO Ka = 3.0×10^(-8)