NDA || SCIENCE || PHYSICS CHEMISTRY || QUIZ

A metal M which is not affected by strong acids like conc. HNO₃, conc. H₂SO₄ and concentrated solutions of alkalies like KOH and NaOH but dissolves in aqua-regia and forms MCl₃ which is used for toning in photography. The metal M is:

The hydrogen ion concentration of three acids P, Q and R are 1 x 10^-5 mol/L, 1 x 10^-3 mol/L and 1 x 10^-2 mol/L respectively. Choose the correct order of their increasing acidic strength.

In a balanced equation-

           H₂SO₄ + xHI → H₂S + yI₂ + zH₂O

The values of x, y, z are                

Consider the following reaction:

Fe₃O₄ + 4H₂ → 3Fe + 4H₂O

Which of the following about the reaction given above is/are correct?

1) Iron is oxidized

2) Hydrogen is oxidised

3) Iron is reduced

4) Hydrogen is reduced

The difference in the mass of 100 moles each of sodium atoms and sodium ions is 0.0238002 g. Calculate the mass of an electron.