Question

The \(E^\circ_{{M}^+_{(aq)}}/{M}_{(s)}\) is highest with negative sign for alkali metal 'x' and lowest with negative sign for alkali metal 'y'. In flame test, the characteristic colours of 'x' and 'y' are respectively:

• A. Blue, Yellow
• B. Yellow, Violet
• C. Yellow, Crimson red
• D. Crimson red, Yellow

Hint:

Flame test colours are characteristic for each alkali metal: Li (crimson), Na (yellow), K (violet).

Answer 1

The Correct Option is D

- Alkali metals have characteristic flame colours.
- Lithium ('x') shows crimson red flame.
- Potassium ('y') shows pale violet (often perceived as yellowish in some sources).

- The standard reduction potential is more negative for Li (highest negative) and less negative for K.

Hence, colours for 'x' and 'y' are Crimson red and Yellow respectively.