At 4^oC , ionic product of water (K\(\omega\)) is 10^-16 . At this temperature, a solution has pH = 7.5 . The nature of this solution at 4^oC will be 

1. Acidic 

2. Alkaline 

3. Neutral

4. Cannot be predicted 

pH of a saturated solution of \(Ca \left(OH\right)_{2}\) is 9. The solubility product \(K_{sp}\) of \(Ca \left(OH\right)_{2}\) is:
1. \(0 . 5 \times \left(10\right)^{- 10}\)
2. \(0 . 5 \times \left(10\right)^{- 15}\)
3. \(0 . 25 \times \left(10\right)^{- 10}\)
4. \(0 . 125 \times \left(10\right)^{- 15}\)