Determining the type of reaction

[reising1]

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1001 EK Chem

867. Consider the following reaction:
CaF2 + H2SO4 --> CaSO4 + 2HF
What type of reaction is this?
A. Bronsted-Lowry acid/base
B. Oxidation/reduction
C. Combustion
D. Dcomposition
Answer: A

I automatically eliminated C because O2 is not a reactant. But how can I determine the answer?

 

[dcamkl1]

You can eliminate D, as well; in decomposition reactions, usually one reactant is broken down in to multiple products (ex: CaSO3 -> SO2 + CaO).

It is not a redox reaction because the oxidation states do not change. I would look at the oxidation state of S because it's easier; in H2SO4, S has an oxidation state of +6, and in CaSO4, the S still has an oxidation of +6, so there is no change. Eliminate B.

If "double-displacement reaction" was used instead of Bronsted-Lowry, it might've been easier to pick out the right answer.

 

[reising1]

You can eliminate D, as well; in decomposition reactions, usually one reactant is broken down in to multiple products (ex: CaSO3 -> SO2 + CaO).

It is not a redox reaction because the oxidation states do not change. I would look at the oxidation state of S because it's easier; in H2SO4, S has an oxidation state of +6, and in CaSO4, the S still has an oxidation of +6, so there is no change. Eliminate B.

If "double-displacement reaction" was used instead of Bronsted-Lowry, it might've been easier to pick out the right answer.

So there's no way to do this without using process of elimination? My question was more so: how can you identify an acid/base reaction?

 

[HesitantManatee]

So there's no way to do this without using process of elimination? My question was more so: how can you identify an acid/base reaction?

You have to know the common acids and bases. But PoE is viable way of doing this type of problem.