A. : In this reaction one of the product, FeS is insoluble. Therefore, this is a precipitation reaction.
B. : In this reaction, the product is a solid(insoluble). So, this is a precipitation reaction too.
C.: In this reaction, both the products are soluble. So this is not a precipitation reaction.
D.: In this reaction, both the products are soluble. So this is not a precipitation reaction.
E. : In this reaction, the product AgCl is a precipitate. So, it is a precipitation reaction.
You put precipitation in the wrong place the answer is D+A (number 4)
The answer is 25 grams for this question