Color they look the same hope this helps.
Answer:
CO32−
Explanation:
We have to consider the valencies of the polyatomic ions involved. Recall that it is only a polyatomic ion with a valency of -2 that can form a compound which requires two sodium ions.
When we look closely at the options, we will realize that among all the options, only CO32− has a valency of -2, hence it must be the required answer. In order to be double sure, we put down the ionic reaction equation as follows;
2Na^+(aq) + CO3^2-(aq) ---------> Na2CO3(aq)
I think the best word here would be compress. It is to compress that is defined as to squeeze a gas into a smaller space. Compression is the reduction of volume which cause an increase in pressure of the gas. Hope this answers the question. Have a nice day.
THE ANSWER IS B SORRY FOR THE CAPS(: