Aluminium oxide contains 52.90% aluminium and carbon dioxide contains 27.27% carbon. Calculate the percentage of aluminium in aluminium carbide assuming that the law of reciprocal proportions is true.

Explanation

Aluuminium oxide contains : `Al = 52.9` parts, `O = 47.1` parts Carbon dioxide contains: `C = 27.27` parts, `O = 72.73` parts
According to the law of reciprocal proportions, the weights of `Al` anc `C` that would combine with each other to form aluminium carbide would either be the same or simple multiple of their that combine with the same weight of oxygen in aluminium oxide and carbon dioxide.
Hence, the weight of carbon that would combine with
`47.1 g` of oxygen in `CO_(2) = (27.27 xx 47.1)/(72.73) = 17.62`, as also, in aluminium oxide, `52.9 g` of `Al` combine with `47.1 g` of oxygen.
Thus, aluminium and carbon should be present in aluminium carbide in the ratio of `52.9 : 17.62`, i.e., `3 : 1` or a simple multiple of this ratio. Hence, in aluminium carbide, percent of `Al = (52. xx 100)/(70.52) = 75.01`.