Answer:
NH4+
Explanation:
A Lewis base is a substance with the ability to share or give pairs of electrons.
The NH4 + ammonium ion donates a proton, therefore the ammonium ion is a Lewis acid.
K will give up an electron more easily than Br.
The chemical bonds in CH4 are all single bonds. C only can bond 4 times because it needs 8 electrons in it's outer shell and only has four right now. The bonds represented are all single bonds because there are two electrons present on each side of the carbon. Two electrons, in this case, equals one bond.
Ba²⁺ + 2Cl⁻ + 2H⁺ + SO₄²⁻ = BaSO₄ (precipitate) + 2H⁺ + 2Cl⁻
Ba²⁺ + SO₄²⁻ = BaSO₄