Starch paper is used to test for the presence of

Which of the following salts does not give a borax bead test?

Which of the following solid salt on heating with solid $K_2Cr_2O_7$ and conc. $H_2SO_4$ evolves orange-red vapours that turn an aqueous $NaOH$ solution yellow?

While preparing crystals of Mohr's salt,dil. $H_2SO_4$ is added to a mixture of ferrous sulphate and ammonium sulphate,before dissolving this mixture in water,dil. $H_2SO_4$ is added here to:

Assign $A, B, C, D$ from the given type of reaction.
$MCrO_4 \downarrow (M^{2+} = Ba^{2+}, Pb^{2+}) + AcOH \longrightarrow$ No dissolution

Which one of the following metals will give blue ash when its salt is heated with $Na_2CO_3$ solid and $Co(NO_3)_2$ on a charcoal piece?