When the compound, na2s, is mixed with water, the na2s is:

soluble because all na+1 compounds are soluble in water

insoluble because most na+1 compounds are insoluble in water

soluble because all s−2 compounds are soluble in water

insoluble because there are no water soluble s−2 compounds

Option (a) is the correct answer.

Explanation:

Atomic number of sodium is 11 and its electronic distribution is 2, 8, 1. Whereas atomic number of sulfur is 16 and its electronic distribution is 2, 8, 6.

So, when both sodium and sulfur chemically combine together then it results in the formation of an ionic bond due to transfer of an electron from sodium to sulfur atom.

Sodium changes into by losing an electron and sulfur changes into by gain of two electrons from two sodium atoms.

As it is known that water is a polar solvent and all ionic substances will dissolve in water.

Therefore, we can conclude that when the compound, , is mixed with water, the is soluble because all compounds are soluble in water.

the correct answer is:

a. formation of precipitation

answer: they produce more slow than unicellular organisms.