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Avariable that is not being directly tested during an experiment should be

Phosphorous can form an ion called phosphide, which has the formula p3−. this ion can form an ion called phosphide, which has the formula p3−. this ion properties very similar to those of pforms when a phosphorus atom loses three protonsis called a cationcontains 18 electrons

Determine type of reaction & predict the product c3h12+o2 =