B,speedof light>speed of sound
Answer:- B- 
Explanations:- Sharing of electrons takes place between non metals and the bond formed by the sharing of electrons is known as covalent bond. In first choice we only have a zinc metal and so no sharing of electrons would be possible here.
In third choice we have NaCl. Na is a metal and Cl is a non metal. The property of metals is to transfer its valence electrons to the non metal and the bond formed is known as ionic bond. So, third choice is also not correct.
In choice B we have sulfate ion that has sulfur and oxygen atoms and both of these are non metals. So, sharing of electrons is present here between the S and O atoms and covalent bonds are formed.
So, choice B-
is the right answer.
Answer:
- <em><u>Option a. no change</u></em>
Explanation:
The question makes sense only if the equation is an equilibrium reaction:
- <em>4A (g) + 5B (g) ⇄ 2C (g) + 7D (g) </em>
This is, A and B react to produce C and D, forward reaction; and C and D react to form A and B, reverse reaction.
Then, you can study the effect of increased pressure using LeChatelier's principle.
To counteract the disturbing effect produced by increased pressure on the equilibrium, the system will react shifting the toward to the side where the pressure could be decreased.
That would be toward the side that has less gas molecules.
Since both sides have 9 molecules (4 + 5 = 2 + 7 = 9), the equilibrium concetrations will not change.
That is represented by the first choice: no change.