A precipitation reaction is a reaction that yields an insoluble product.
When two solutions which could react are mixed together, they interact with each other and products are formed. These products could be aqueous solutions or solids.
When a mixture of two aqueous solutions react chemically to yield an insoluble product, we can say that a precipitation reaction has taken place.
We shall now proceed to fill in the missing products in each of the reactions;
a) Ca(NO3)2 (aq) + CuSO4 (aq) → CaSO4(s) + Cu(NO3)2 (aq)
b) 2KC2H302 (aq) + COSO4 (aq) → Co(C2H302)2 (s) + K2SO4(aq)
c) 2K3PO4 (aq) + 3Mg12 (aq) → 6KI(aq) + Mg3(PO4)2 (s)
d) FeCl3 (aq) + 3NH4OH (aq) → Fe(OH)3 (s) + 3NH4Cl(aq)
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The correct answer is letter (A) Acetylene. Acetylene is the most simplest form of alkyne and at the same time a hydrocarbon. It is unsaturated because of the presence of only two carbon atoms that are bonded together in a triple bond. I<span>n its pure, it is unstable and thus, it is usually held and handled as a solution.</span>