When magnesium ribbon is ignited, it gives off a white fume of magnesium oxide. what is this type of reaction?
a.
double displacement reaction
b.
single displacement reaction
c.
decomposition reaction
d.
synthesis reaction

D.  synthesis reaction

Explanation:

A. Double displacement reaction

This reaction is defined as the chemical reaction in which exchange of ions takes place.

B. Single displacement reaction

This reaction is defined as the chemical reaction in which more reactive element displaces a less reactive element from its chemical reaction.

C. Decomposition reaction

This reaction is defined as the chemical reaction in which a single substance breaks down into two or more simpler substances.

D. Synthesis reaction

This reaction is defined as the chemical reaction in which substances combine in their elemental state to form a single compound.

Thus it is a synthesis reaction.

explanation:

v=uf/(u-f)

= 5.-10/(5+10) convex lens has negative focal length