[bdtgat]

Hello.
There is this question that I think is both Redox and Synthesis, but the answer can only be one of the two. One of the answers is probably better than the other. Could someone please explain? Here is the Question:

Balance the equation and identify the type of reaction for:
?P₄(s) + ?Ca(s)  ?Ca₃P₂(s)

A. 1;6;2;- redox
B. 2;6;2 - synthesis
C. 2;6;2 - decomposition
D. 2;6;2 - redox
E. 1;6;2 -synthesis
F. 1;6;2 - decomposition

Its obviously a redox or a synthesis reaction, and not a decomposition, so that eliminates choices C and F. A product is created, not destroyed.
Answer choices B and D are wrong because the coefficients are wrong.
Its either answer choice A or E. They both have the coefficients right, and I believe the reaction is both Synthesis (1 product is being created {product A + product B= Product AB}) and redox (oxidation numbers are changing). However, there can only be one answer. Someone please help?

[Archer]

You should start by balancing the equation, then look at the product and the oxidation states of the P and Ca.

Have you made a molecule or have you made an ionic compound in this reaction?

[Borek]

Its either answer choice A or E. They both have the coefficients right, and I believe the reaction is both Synthesis (1 product is being created {product A + product B= Product AB}) and redox (oxidation numbers are changing). However, there can only be one answer. Someone please help?

You are perfectly right and answers are poorly selected. It is both synthesis and redox at the same time, these are not opposites.

[Archer]

You are perfectly right and answers are poorly selected. It is both synthesis and redox at the same time, these are not opposites.

I agree with you but I think that the question has been written by a chemist whose idea of "synthesis" is covalent bond formation / cleavage of organic compounds.

As this is inorganic they probably consider that it is not synthesis but a redox reaction.

It's a bit like asking how to "synthesise" sodium chloride from sodium and chlorine, can you call this a synthesis or would it be better described as a preparation? This comes down, in part, to semantics in my view. Either way 2Na + Cl₂ 2NaCl would be redox.

Not a well thought out question, one wonders what the question setter would make of permanganate oxidation of alcohols to ketones, synthesis or redox?

[Borek]

In High School chemical reactions are classified as four basic "types" - synthesis, decomposition, single replacement and double replacement (AKA metathesis).

We can discuss whether this classification makes sense, but as it is one of the first things taught in the HS chemistry, looking for other meanings in this context means just confusing students.