Explanation:

To determine whether a solution is basic or acidic, we need to look at the ions present in the solution and their ability to accept or donate protons (H+ ions).

In this case, we are given a 0.1 M solution of four substances: sodium borate, ammonium chloride, calcium nitrate, and sodium sulfate. We need to identify which one of these substances will react basic.

1. Sodium Borate (Na2B4O7):
- Sodium borate is a salt that dissociates in water to form sodium ions (Na+) and borate ions (B4O7^2-).
- The borate ion (B4O7^2-) can accept protons from water molecules, making the solution basic.
- Therefore, a 0.1 M solution of sodium borate will react basic.

2. Ammonium Chloride (NH4Cl):
- Ammonium chloride is a salt that dissociates in water to form ammonium ions (NH4+) and chloride ions (Cl-).
- Neither the ammonium ion nor the chloride ion has the ability to accept or donate protons, so the solution will not be basic.
- Therefore, a 0.1 M solution of ammonium chloride will not react basic.

3. Calcium Nitrate (Ca(NO3)2):
- Calcium nitrate is a salt that dissociates in water to form calcium ions (Ca^2+) and nitrate ions (NO3-).
- Neither the calcium ion nor the nitrate ion has the ability to accept or donate protons, so the solution will not be basic.
- Therefore, a 0.1 M solution of calcium nitrate will not react basic.

4. Sodium Sulfate (Na2SO4):
- Sodium sulfate is a salt that dissociates in water to form sodium ions (Na+) and sulfate ions (SO4^2-).
- Neither the sodium ion nor the sulfate ion has the ability to accept or donate protons, so the solution will not be basic.
- Therefore, a 0.1 M solution of sodium sulfate will not react basic.

Conclusion:
Among the given substances, only sodium borate (option A) will react basic in a 0.1 M solution. Ammonium chloride, calcium nitrate, and sodium sulfate will not react basic in the given concentration.

Na2B4O7.10H2O (sodium borate ) when dissolve in water form give alkaline solution , Na2B4O7+7H2O-----> NaOH+ H3BO3 , here NaOH is strong base and H3BO3 is weak acid so overall it is basic . option B is incorrect NH4Cl+ H2O -----> NH4OH (weak base)+ HCl(strong acid) , in option C ,. CaCO3 +H2O----> Ca(OH)2{strong base}+ H2CO3(strong acid) means overall it is neutral. . in option D ., Na2SO4+H2O-----> NaOH(strong base)+ H2SO4 (strong acid) it is overall neutral so option A is correct