If steel is heated to a temperature well below red heat and is then cooled slowly,the process is called

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?

Which pair of cations can be identified by the borax bead test?

Match List-$I$ with List-$II$:

List-$I$ Solid salt treated with dil. $H_2SO_4$	List-$II$ Anion detected
$A.$ Effervescence of colourless gas	$I.$ $NO_2^-$
$B.$ Gas with smell of rotten egg	$II.$ $CO_3^{2-}$
$C.$ Yellowish green gas with pungent and suffocating smell	$III.$ $S^{2-}$
$D.$ Brown fumes	$IV.$ $Cl^{-}$

Choose the correct answer from the options given below:

The microcosmic salt is

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?