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.
Answer:
Covalent bonding is the sharing of electrons between atoms. In addition, the ionization energy of the atom is too large and the electron affinity of the atom is too small for ionic bonding to occur.
For example: carbon does not form ionic bonds because it has 4 valence electrons, half of an octet.
Explanation:
J.J Thompson’s model shows a sphere with electrons that are moving around freely. However, Thompson’s model does not show protons or neutrons. The model that we have today gives a clearer structure showing protons, neutrons, and electrons inside an atom.
The solubility rules usually go on to say that group IIA sulfides are soluble, but actually group IIA sulfides react with water to make H2S and the group IIA metal hydroxide.
Answer:
is there a pic or anything?