Question

Which of the following method has been used to prepare the single crystals of CaO using plasma torch?

(a) Stockbarger method

(b) Zone melting method

(c) Verneuil flame fusion method

(d) Bridgman method

This question was addressed to me in my homework.

Question is taken from Growth of Single Crystals topic in portion Preparative Methods of Solid State Chemistry

Answer 1

Correct option is (c) Verneuil flame fusion method

For explanation I would say: Verneuil flame fusion method has been recently used to prepare the single crystals of CaO with a melting point equal to 2600◦C by using a plasma torch to melt the CaO powder. The starting material in the form of a fine powder is passed through an oxyhydrogen flame or some other high temperature torch or furnace after melting has taken place, the droplets fall onto the surface of the growing crystals where they solidify.