I think the answer is 42kg m/s.
The answer is Bantu.
They had already developed immunity to malaria due to exposure in their native environment.
As they migrated southwards to conquer more land, they met the pygmies and the Khoisan. The Bantus had carried with them the malaria vectors.
When the mosquitos infected the pygmies
and the Khoisan populations, who had no
immunity against malaria, the disease reduced their populations drastically hence
enabling the Bantus to conquer their
land.
Most organic acids are weak. Hydrogen fluoride (dissolving in water to produce hydrofluoric acid) is a weak inorganic acid that you may come across elsewhere.
...
acid Ka (mol dm-3)
hydrofluoric acid 5.6 x 10-4
methanoic acid 1.6 x 10-4
ethanoic acid 1.7 x 10-5
hydrogen sulphide 8.9 x 10-8
