Question

Why is magnesium ribbon chosen and not magnesium rod in burning experiments?

Answer 1

Hint: Magnesium ribbon and magnesium rod are both same types of magnesium only. The only difference is that a magnesium ribbon is very thin with a thickness less than 0.1 millimeters while a rod on the other hand has a significantly larger thickness. To answer this question, you must recall the necessities for a laboratory experiment and then compare it with the properties of both the types of substances.

Complete step by step solution
The reasons as to why we choose a magnesium ribbon over a magnesium rod for burning experiments are:
Since the reaction proceeds at a very high temperature, it is easier to heat the ribbon upto the required temperature using a simple splinter. A rod which is comparatively thicker would take longer to heat or may not even burn in air using a splinter depending upon its thickness. The higher surface area of the magnesium ribbon provides increased exposure to more nitrogen molecules and thus ensuring complete burning of magnesium. In case of a rod, the magnesium nitride powder if formed would deposit on the surface of the rod and would hinder the progress of the reaction.

Note
We know that magnesium is an alkaline earth metal having the atomic number 2. It is a highly reactive metal and the only group 2 metal that can burn in air and react with nitrogen to form a nitride. The burning reaction of magnesium ribbon is a highly exothermic one and takes place at high temperature of around 800 degree Celsius. Magnesium nitride formed is a greenish yellow coloured powder.