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)
Answer:
Hydrogen sulfide
Explanation:
A nonoxidizing acid is the acid which cannot act as oxidizing agent and thus furnish hydrogen ions. Example: HCl
Iron(II) sulfide reacts with nonoxidizing acid, say hydrochloric acid to give rotten egg smelling gas, H₂S (Hydrogen sulfide).
The reaction is shown below:
FeS (s) + 2HCl (aq) ⇒ FeCl₂ (s) + H₂S (g)
A general reaction is also shown below of the reaction of Iron(II) sulfide with any nonoxidizing acid, HX as:
FeS (s) + 2HX (aq) ⇒ FeX₂ (s) + H₂S (g)
Answer:
Cost to supply enough vanillin is 
Explanation:
Threshold limit of vanillin in air is 
per litre means there should be of vanillin in 1L of air to detect aroma of vanillin.
So, 
So amount of vanillin should be present to detect = 
As cost of 50 g vanillin is 
therefore cost of vanillin = 
I was going to help but I don’t understand the question
