Alkalinity in water is due to  0 pointsOH–Carbonate ionsBicarbonate ionsAll of the above

Analyzing the Options

1. Hydroxide ions (OH⁻): These ions contribute to the alkalinity of water by increasing the pH and neutralizing acids.

2. Carbonate ions (CO₃²⁻): These ions also contribute to alkalinity as they can react with acids to maintain a stable pH.

3. Bicarbonate ions (HCO₃⁻): These ions act as a buffer in water, helping to maintain pH levels and contributing to alkalinity.

Conclusion

All three components (OH⁻, carbonate ions, and bicarbonate ions) contribute to the alkalinity of water. Therefore, the correct choice is:

Answer: All of the above.

In summary, alkalinity in water arises from a combination of hydroxide ions, carbonate ions, and bicarbonate ions, each playing a role in buffering and maintaining proper pH levels.