Question

Which metal gives golden yellow colour in flame test?
A. ${K^ + }$
B. $N{a^ + }$
C. $P$
D. $C{l^ - }$

Answer 1

In chemistry, a flame test is used to identify the presence of metal ions in the given compound on the basis of the colours in the flame test.

Complete step by step answer:
For the flame test, a Bunsen burner is used to give a hot and non-luminous flame. The compound sample to be tested is taken, which is then kept in the flame for sometime and the colour of the flame is observed.
As obvious, different colours red, yellow, green, orange, etc. are imported during this test by different metal ions.
The reason for this colour lies in the electron transitions within an atom. When a compound is kept in flame, the electrons get heated and acquire energy. Due to this energy, the electrons start jumping from their ground state to an excited state. During their return to the ground state some amount of energy is released which is in the form of light of different colours. Thus, upon electronic transitions, light is emitted and it provides a characteristic colour to the flame.
Flame test is an easy experiment and is commonly performed in school laboratories.
For better results, a clean platinum wire is used. Paste a compound is made with concentrated hydrochloric acid and then subjected to the flame. After, every test the platinum wire is cleaned with hydrochloric acid to remove traces of compound from it.

Some colours of flame imparted by metal ions are:
I.Silver white colour aluminium
II.Bright green colour by boron
III.Crimson colour by strontium
IV.Yellowish green colour by molybdenum
V.Golden yellow colour by sodium, etc.

So, the correct answer is Option B.

Note:
Sometimes, wrong colours of flames are shown due to contamination. Therefore, it is necessary to clean the platinum wire every time before else. Also, one test should be performed $2 - 3$ times to get accurate results of the flame test.