測ph值用的工具....

正確答案應為 pH indicator, pH meter 及 pH paper.

因litmus paper只能測該物品是酸還是鹼, 而不是 pH value.

說明:

pH can be measured:

by addition of a pH indicator into the solution under study. The indicator color varies depending on the pH of the solution. Using indicators, qualitative determinations can be made with universal indicators that have broad color variability over a wide pH range and quantitative determinations can be made using indicators that have strong color variability over a small pH range. Extremely precise measurements can be made over a wide pH range using indicators that have multiple equilibriums in conjunction with spectrophotometric methods to determine the relative abundance of each pH-dependent component that make up the color of solution, orby using a pH meter together with pH-selective electrodes (pH glass electrode, hydrogen electrode, quinhydrone electrode, ion sensitive field effect transistor and others).by using pH paper, indicator paper that turns color corresponding to a pH on a color key. pH paper is usually small strips of paper (or a continuous tape that can be torn) that has been soaked in an indicator solution, and is used for approximations.

因為red litmus paper和blue litmus paper
只係可以測試y溶液係酸或鹼,而唔可以知道
那一樣的溶液的ph值!!!
而pH paper可以測試y溶液,得出的顏色,再用色紙對返顏色,那便
能知道ph值係幾多啦........

red litmus paper係遇鹼先會變成藍色,
遇酸係唔會變色的......
而blue litmus paper遇酸會變紅色
遇鹼係唔會變色的.......

Because litmus paper only find out whether the solution is acidic or alkaline.
If the solution is acidic, you use wet red litmus paper to test , you just get nothing about the conclusion.
If the solution is alkaline, you use blue litmus paper to test , you just get nothing about the conclusion.

On the contrary, PH paper can show the colour. If it is acidic,the colour will tent to red.
If it is alkaline, the colour will tend to blue.


Wet red litmus paper will change colour if the solution is alkaline.（遇鹼）