Which of the following substances will react with concentrated $H_2SO_4$?

Which of the following explains why sodium metal exhibits metallic luster?

Potassium permanganate,on heating,gives:

Which one of the following statements is correct?

Which of the following orders is correct with respect to the magnitude of enthalpies of formation for alkali metal halides?

The correct order of hydration enthalpies is
$A. K^{+}$; $B. Rb^{+}$; $C. Mg^{2+}$; $D. Cs^{+}$; $E. Ca^{2+}$
Choose the correct answer from the options given below: