Question

A substance $X$ is a compound of $s-$ block element, substance $X$ gives a violet colour in flame test, $X$ is :

• A. $LiCl$
• B. $MgC{l}_2$
• C. $BaC{l}_2$
• D. $KCl$

Answer 1

The correct option is D $KCl$

Flame test is used to identify the metal by their characteristic colour while heating in a oxidising flame.
The heat from the flame excite the outer electron to higher energy level and when they comes back to ground state they emit the absorb energy where these radiation in visible region shows characteristic colour

In the flame test,
$KCl$ gives violet colour
$LiCl$ gives crimson red colour
$BaC{l}_2$ gives pale green colour
$MgC{l}_2$ gives no colour in flame test