Question

Magnesium ribbon is burnt in an atmosphere of nitrogen gas to form solid magnesium nitride. This is a
A.Synthesis reaction
B.Combination reaction
C.Displacement reaction
D.None of the above

Answer 1

Hint: we have been given a magnesium ribbon which is being burnt in an atmosphere of nitrogen gas. Here nitrogen and magnesium are combined to form magnesium nitride. We can also say that we are using nitrogen and magnesium for the synthesis of magnesium nitride.

Complete Step-by-step Solution:
Let us first see what each of the reactions mean:
Synthesis reaction: When two or more reactants combine with each other to synthesize a new product , it is called synthesis reaction.
\[A + B \to AB\]
Here , \[AB\] is being synthesized.
Combination reaction: When two or more elements or compounds combine to form a single product, this is called combination reaction.
\[X + Y \to XY\]
Reactants can be compound or element.
Displacement reaction: A chemical reaction in which the more reactive element replaces the less reactive element is called displacement reaction.
\[A + BC \to AC + B\]
Here , \[A\] is more reactive than \[B\] and hence replaced it in the above reaction.
Which metal is more reactive or which is less reactive is determined by the reactivity series. The metals at the top are highly reactive and metals at bottom are less reactive.

Now we will look at the reaction that is given to us :
\[3Mg + {N_2} \to M{g_3}{N_2}\]
From the above definitions , it looks like it can either be a combination or synthesis reaction.
Both nitrogen and magnesium being reactants react to form a single product.

Hence, the correct options are A and B.

Note: We need to keep one thing in mind that in combination and synthesis we are more likely to get a single product only. Reactants can either be compound or element but the product is always a compound.