For the reaction between aqueous calcium nitrate and aqueous sodium hydroxide producing the precipitate (solid) calcium hydroxide and aqueous sodium nitrate (a) write a balanced equation for this reaction
(b) classify the reaction

The given reaction is a substitution reaction in which hydroxil group is exchanged between compounds.

Substitution Reaction:

It is a reaction in which functional group of a compound replaced by the another functional group.

For example-

In the reaction hydroxil group is exchanged between compounds.

1 mole of aqueous calcium nitrate react with  2 moles aqueous sodium hydroxide to produce  1 mole of solid precipitate calcium hydroxide and 2 moles aqueous sodium nitrate.

Therefore, the given reaction is a substitution reaction in which hydroxil group is exchanged between compounds.

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Ca(NO3)2(aq) + 2NaOH(aq) —> Ca(OH)2(s) + 2NaNO3(aq)

Substitution

Explanation:

as given the equation is

2al + 6 hcl > 2 alcl3 + 3 h2(g)

as per equation two moles of aluminum reacts with six moles of hcl to give two moles of alcl3 and three moles of hydrogen gas

given: three moles of al are present and 7 moles of hcl

for three moles of aluminum nine moles of hcl will be required

however as 7 moles of hcl are present so the limiting reagent is hcl

hcl is going to decide the number of moles of product formed

when six moles of hcl are present = 3 moles of h2 are formed

when one mole of hcl is present == 3/6 mole sof h2 will be formed

when 7 moles of hcl are present = 3 x 7/ 6 moles of h2 will be formed = 3.5 moles of h2