Which of the following is not correct regrading lanthanoids ?

Options

A. Neodymium oxide is used as a most poweful liquid lasers lanthanide it in selenium oxychloride
B. If the lanthanide with nf electrons has a pink color, then the lanthanide with (14 - n) f electrons will be colorless.
C. Pr and Nd lanthanoids are used inglass blower's goggles
D. The best single use of lanthanoids is for the production of alloy steels for plates and pipes

Answer

B

Explanation

Elements with (n)f electrons often have a similar color to those with (14 - n)f electrons. A well-known alloy is mischmetal which consists of a lanthanoid metal `(~ 95%)` and iron `(~ 5%)` and traces of S, C, Ca and Al. A good deal of mischmetal is used in Mg-based alloy to produce bullets, shell and lighter flint. Mixed oxides of lanthanoids are employed as catalysts in petroleum caracking.