Epsilon-delta would be the green letter that is used in the precision definition of a limit. (ε, δ).
B----------- oxide is the correct answer
Iron sulfide is a<span> mixture of iron filings and sulfur will make the iron and sulfur atoms combine chemically.
Hope this helps :)</span>
<span>1) 0.2M ferric nitrate is added gradually to 1M sodium hydroxide. In result, a red precipitate appears. The precipitate is ferric hydroxide.
2) </span><span>0.2M potassium chromate is added gradually to 0.05M lead acetate. in result, a yellow precipitate appears. The precipitate is called potassium acetate.
The common between the two is that the colors originated from one of the reactants. </span>
