6. A 7.0 × 10-3 M aqueous solution of Ca(OH)2 at 25.0°C has a pH of __________.

Question

6. A 7.0 × 10-3 M aqueous solution of Ca(OH)2 at 25.0°C has a pH of __________.

A) 12.15

B) 1.85

C) 1.4 × 10-2

D) 7.1 × 10-13

E) 11.85

7. According to Lewis theory, a Lewis base is a(n)

A) proton donor

B) proton acceptor

C) electron-pair donor

D) electron-pair acceptor

E) none of the above.

8. The concentration of Mg in seawater is 0.054 M. How many grams of Mg can be extracted from 10.0 kg of seawater if the recovery rate is 20.0%?

A) 13. 9

B) 6.50

C) 11.3

D) 2.62

E) 5.25

9. The concentration of iodide ions in a saturated solution of lead (II) iodide is __________ M. The solubility product constant of PbI2 is 1.4 × 10-8.

A) 3.8 × 10-4

B) 3.0 × 10-3

C) 1.5 × 10-3

D) 3.5 × 10-9

E) 1.4 × 10-8

10. The Henderson-Hasselbalch equation is __________.

Explanation / Answer

6) first of all we need to calculate the total concentration bof OH- ion,

Ca(OH)2 --------> Ca+2 + 2OH-

Thus, [OH-] = 2x7.0x10-3 = 14x10-3M

pOH = - log[OH-]

= -log[14x10-3]

= 1.8

pH = 14-pOH

= 14- 1.8

= 12.1

So the answer is the first option.

7) according to Lewis acid base theory, electron pair donor is acid and electron pair donor is the base.

Examples, acid: AlCl3, FeCl3 and bases : NH3.

I am sorry I am not supposed to do more than one question when multiple questions were being asked according to our guidelines.

But I did 2 for you.

Thank you

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