Question

3. Which ONE of the following solids when added to 1 L of water will change the pH from 2.80 to 6.25? (N.B. there is no change in volume).

4. A) 2.53 x 10–3 mol LiOH

5. B) 1.58 x 10–3 mol NaOH

6. C) 1.02 x 10–2 mol KOH

7. D) 4.42 x 10–2 mol Ca(OH)2

8. E) 6.19 x 10–3 mol RbOH

Answer 1

Soli Llink) d arity - day I here: V=12 .. Here: Molarity > moles ! pH changing from 2.80 to 6.25 27: still acidic {{Hz ot} remaing in solution. pH = -log Cat} = 2.80 => (H [ht at 2.8 pH aton = 10 =0.00158489M -6.28 pH = -log(+3 = 6.25 Chat are 106.25 5. 62 34x107m Let Con added = xM ar pH-6.25 = 5.6234X10 M M
.
Now [Now] Cat} + Cot] Hoo Before reaction) 0.0015848am After Jo.0015 88 89-x) se Ssact on | 37 Ñ 5.6234x, => 0.00158489x = 5.6234X10 = x=((0.00158493-{(5.6234x107)] = 0.0015843 [NO OH} ~[ok] ~ * ~o galing strong, ~ 1.558x103 Base M ∞ 158 xio mol option ③: 1.5x 103 mol Naot v