Question

an element burns with a dazzling light forming a compound which when dissolved in water changes red litmus blue identify the element and write down the reaction involved

Answer 1

I think it's MgO ( Magnesium Oxide)

Answer 2

Explanation:

Magnesium metal burns with white flame under the action of oxygen gas to give magnesium oxide as a product which basic in nature.

$2Mg(s)+O_2(g)\rightarrow 2MgO(s)$

When this oxide of magnesium is dissolved in water it forma an alkaline solution of magnesium hydroxide. And this basic solution turns the color of red litmus to blue.

$MgO(s)+H_2O(l)\rightarrow Mg(OH)_2(s)$