The formula of the purple colour formed in Laissaigne's test for sulphur using sodium nitroprusside is :

Given below are two statements :

Statement I : In 'Lassaigne's Test', when both nitrogen and sulphur are present in an organic compound, sodium thiocyanate is formed.

Statement II : If both nitrogen and sulphur are present in an organic compound, then the excess of sodium used in sodium fusion will decompose the sodium thiocyanate formed to give NaCN and Na₂S.

In the light of the above statements, choose the most appropriate answer from the options given below :

During halogen test, sodium fusion extract is boiled with concentrated HNO₃ to

In the flame test of a mixture of salts, a green flame with blue centre was observed. Which one of the following cations may be present?