hok ling asked in 科學及數學化學 · 1 decade ago

acid alkali 問題(urgent)

which of the following when added to 10cm3 of 0.1M NaOH solution,would change the pH value of NaOH solution?

(1).10cm3 of 0.1M NaCl solution.

(2)5cm3 of 0.1M KOH solution

(3)10cm3 of distilled water

A. 1 and 2

B. 1 and 3

C. 2 and 3

D. 1, 2 and 3

正確答案係B

我想知點解NaCl得同KOH唔得??

2 Answers

Rating
  • pha
    Lv 7
    1 decade ago
    Favorite Answer

    It is easy to note down the answer even without seeing your solution.

    1. NaCl solution can change the pH of the alkali. It is trivial that NaCl is considered to be neutral with a pH value of 7 at 25 degree celcius. However, it has volume and this dilution would change the pH of the alkali slightly.

    2. KOH: The problem is not KOH. The main reason is that the concentration of KOH is the same as that of NaOH, your original alkali. Hence, same pH solution mixed together would not change the pH of the other solution.

    Source(s): ME
  • 1 decade ago

    加5cm3 of 0.1M KOH,同再加NaOH冇分別,因兩者都係monobasic,一樣都係0.1M,所以兩者的OH- ions濃度一樣。

    Source(s): Myself
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