Which laboratory results will tell whether an unknown white solid is $\mathrm{NaOH}$ or ${\mathrm{NH}}_4{\mathrm{NO}}_3$ ?

$\mathrm{NaOH}$ is soluble in ${\mathrm{H}}_2\mathrm{O}$  but ${\mathrm{NH}}_4{\mathrm{NO}}_3$ is not.

Aqueous $\mathrm{NaOH}$ turns litmus blue but ${\mathrm{NH}}_4{\mathrm{NO}}_3$ does not.

Aqueous $\mathrm{NaOH}$ reacts with copper metal but ${\mathrm{NH}}_4{\mathrm{NO}}_3$ does not

$\mathrm{NaOH}$ gives a green flame test but ${\mathrm{NH}}_4{\mathrm{NO}}_3$ is colourless in a flame.