0.042 M HBr 10.0 mL + 0.70 M NaOH 11.7 mL

0.042 M HBr 10.0 mL + 0.70 M NaOH 11.7 mL

반응 후 용액은 산성, 염기성, 중성? 용액의 색깔은?

 

 

A drop of phenolphthalein is added to

a solution of 0.042 M HBr with a volume of 10.0 mL.

The solution is mixed with 11.7 mL of 0.70 M NaOH.

After the reaction is complete,

is the solution acidic, basic, or neutral?

What color is the indicator?

 

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(0.042 M) (10.0 mL) = 0.42 mmol HBr

( 참고 https://ywpop.tistory.com/7787 )

 

(0.70) (11.7) = 8.19 mmol NaOH

 

 

 

HBr + NaOH → NaBr + H2O

 

HBr : NaOH = 1 : 1 계수비(= 몰수비) 이고,

HBr의 몰수 < NaOH의 몰수 이므로,

반응 후 남아있는 물질 = NaOH

---> 용액은 염기성.

---> 색깔은 분홍색(pink).

( 참고: 페놀프탈레인 https://ywpop.tistory.com/3839 )

 

 

 

 

[FAQ] [①23/06/11]