What are the limitations of litmus paper and Phenolphthalein indicators? Name to other indicators that can be used that do not h
ave such limitations
1 answer:
Answer:
Here's what I find.
Explanation:
An indicator is usually is a weak acid in which the acid and base forms have different colours. Most indicators change colour over a narrow pH range.
(a) Litmus
Litmus is red in acid (< pH 5) and blue in base (> pH 8).
This is a rather wide pH range, so litmus is not much good in titrations.
However, the range is which it changes colour includes pH 7 (neutral), so it is good for distinguishing between acids and bases.
(b) Phenolphthalein
Phenolphthalein is colourless in acid (< pH 8.3) and red in base (> pH 10).
This is a narrow pH range, so phenolphthalein is good for titrating acids with strong bases..
However, it can't distinguish between acids and weakly basic solutions.
It would be colourless in a strongly acid solution with pH =1 and in a basic solution with pH = 8.
(c) Other indicators
Other acid-base indicators have the general limitations as phenolphthalein. Most of them have a small pH range, so they are useful in acid-base titrations.
The only one that could serve as a general acid-base indicator is bromothymol blue, which has a pH range of 6.0 to 7.6.
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The bond is polar covalent because the difference in electronegativity is greater than 0.4, but less than 1.7.
Electronegativity refers to the ability of an atom in a compound to attract the electrons of the bond towards itself. It is a periodic trend that increases across the period but decreases down the group.
The electronegativity difference between the two atoms as shown in the question is 1.55. This means that the bond is polar covalent because the difference in electronegativity is greater than 0.4, but less than 1.7.
Learn more: brainly.com/question/2510654
