Question

3. The number of Al3+ ions in 0.051 g of aluminium
oxide are (Atomic mass of Al = 27 u, O = 16 u)
(a) 6.022 x 1020
(b) 3.3 X 1020
(c) 2.2 x 1020
(d) 6.022 x 1023​

Answer 1

Answer:

Mole of aluminium oxide (Al2O3) = 2 x 27 + 3 x 16

= 102 g

i.e., 102 g of Al2O3= 6.022 x 1023 molecules of Al2O3

Then, 0.051 g of Al2O3 contains = 6.022 x 1023 / 102 x 0.051 molecules

= 3.011 x 1020 molecules of Al2O3

The number of aluminium ions (Al3+) present in one molecule of aluminium oxide is 2.

Answer 2

Answer:

I think c option is right