Answer :
To determine which acid [tex]\((X)\)[/tex] and base [tex]\((Y)\)[/tex] react to produce [tex]\( Mg _3(PO _4)_2 \)[/tex], let's analyze the options step by step:
1. Identify the components needed to form [tex]\( Mg _3(PO _4)_2 \)[/tex]:
- The product [tex]\( Mg _3(PO _4)_2 \)[/tex] contains magnesium (Mg) and the phosphate group (PO4).
- Therefore, the acid [tex]\( X \)[/tex] must provide the PO4 group, and the base [tex]\( Y \)[/tex] must provide the Mg group.
2. Examine the given options:
- Option 1: [tex]\( X = H_3PO_3 \)[/tex]; [tex]\( Y = Mg(OH)_2 \)[/tex]
- [tex]\( H_3PO_3 \)[/tex] is phosphorous acid, which contains the [tex]\( PO_3 \)[/tex] group, not [tex]\( PO_4 \)[/tex].
- This option is incorrect because the product requires the [tex]\( PO_4 \)[/tex] group, not [tex]\( PO_3 \)[/tex].
- Option 2: [tex]\( X = H_3PO_4 \)[/tex]; [tex]\( Y = Mg(OH)_2 \)[/tex]
- [tex]\( H_3PO_4 \)[/tex] is phosphoric acid, which contains the [tex]\( PO_4 \)[/tex] group.
- [tex]\( Mg(OH)_2 \)[/tex] is magnesium hydroxide, which provides the Mg group.
- This option is correct because [tex]\( H_3PO_4 \)[/tex] provides the [tex]\( PO_4 \)[/tex] group, and [tex]\( Mg(OH)_2 \)[/tex] provides the Mg.
- Option 3: [tex]\( X = H_3PO_4 \)[/tex]; [tex]\( Y = Ca(OH)_2 \)[/tex]
- [tex]\( H_3PO_4 \)[/tex] is phosphoric acid, which contains the [tex]\( PO_4 \)[/tex] group.
- [tex]\( Ca(OH)_2 \)[/tex] is calcium hydroxide, which provides the Ca group, not Mg.
- This option is incorrect because the product [tex]\( Mg _3(PO _4)_2 \)[/tex] specifically requires Mg, not Ca.
- Option 4: [tex]\( X = H_3PO_3 \)[/tex]; [tex]\( Y = Ca(OH)_2 \)[/tex]
- [tex]\( H_3PO_3 \)[/tex] is phosphorous acid, which contains the [tex]\( PO_3 \)[/tex] group, not [tex]\( PO_4 \)[/tex].
- [tex]\( Ca(OH)_2 \)[/tex] is calcium hydroxide, which provides the Ca group, not Mg.
- This option is incorrect for two reasons: [tex]\( H_3PO_3 \)[/tex] contains [tex]\( PO_3 \)[/tex] instead of [tex]\( PO_4 \)[/tex], and [tex]\( Ca(OH)_2 \)[/tex] provides Ca instead of Mg.
Hence, the correct pairs that react to form [tex]\( Mg _3(PO _4)_2 \)[/tex] are:
[tex]\[ X = H_3PO_4 \][/tex]
[tex]\[ Y = Mg(OH)_2 \][/tex]
1. Identify the components needed to form [tex]\( Mg _3(PO _4)_2 \)[/tex]:
- The product [tex]\( Mg _3(PO _4)_2 \)[/tex] contains magnesium (Mg) and the phosphate group (PO4).
- Therefore, the acid [tex]\( X \)[/tex] must provide the PO4 group, and the base [tex]\( Y \)[/tex] must provide the Mg group.
2. Examine the given options:
- Option 1: [tex]\( X = H_3PO_3 \)[/tex]; [tex]\( Y = Mg(OH)_2 \)[/tex]
- [tex]\( H_3PO_3 \)[/tex] is phosphorous acid, which contains the [tex]\( PO_3 \)[/tex] group, not [tex]\( PO_4 \)[/tex].
- This option is incorrect because the product requires the [tex]\( PO_4 \)[/tex] group, not [tex]\( PO_3 \)[/tex].
- Option 2: [tex]\( X = H_3PO_4 \)[/tex]; [tex]\( Y = Mg(OH)_2 \)[/tex]
- [tex]\( H_3PO_4 \)[/tex] is phosphoric acid, which contains the [tex]\( PO_4 \)[/tex] group.
- [tex]\( Mg(OH)_2 \)[/tex] is magnesium hydroxide, which provides the Mg group.
- This option is correct because [tex]\( H_3PO_4 \)[/tex] provides the [tex]\( PO_4 \)[/tex] group, and [tex]\( Mg(OH)_2 \)[/tex] provides the Mg.
- Option 3: [tex]\( X = H_3PO_4 \)[/tex]; [tex]\( Y = Ca(OH)_2 \)[/tex]
- [tex]\( H_3PO_4 \)[/tex] is phosphoric acid, which contains the [tex]\( PO_4 \)[/tex] group.
- [tex]\( Ca(OH)_2 \)[/tex] is calcium hydroxide, which provides the Ca group, not Mg.
- This option is incorrect because the product [tex]\( Mg _3(PO _4)_2 \)[/tex] specifically requires Mg, not Ca.
- Option 4: [tex]\( X = H_3PO_3 \)[/tex]; [tex]\( Y = Ca(OH)_2 \)[/tex]
- [tex]\( H_3PO_3 \)[/tex] is phosphorous acid, which contains the [tex]\( PO_3 \)[/tex] group, not [tex]\( PO_4 \)[/tex].
- [tex]\( Ca(OH)_2 \)[/tex] is calcium hydroxide, which provides the Ca group, not Mg.
- This option is incorrect for two reasons: [tex]\( H_3PO_3 \)[/tex] contains [tex]\( PO_3 \)[/tex] instead of [tex]\( PO_4 \)[/tex], and [tex]\( Ca(OH)_2 \)[/tex] provides Ca instead of Mg.
Hence, the correct pairs that react to form [tex]\( Mg _3(PO _4)_2 \)[/tex] are:
[tex]\[ X = H_3PO_4 \][/tex]
[tex]\[ Y = Mg(OH)_2 \][/tex]
