(a) Chromium(III) hydroxide, Cr(OH)3, is only slightly soluble in water. The value of the solubility product, Ksp, of Cr(OH)3 is 1.0 × 10–33 at 298 K.

1. (a)(i)Complete the expression for Ksp of Cr(OH)3. Include the units. Ksp = units =[2]
2. (a)(ii)Calculate the solubility, in gdm³, of Cr(OH)3 in pure water at 298 K. Show your working. solubility =[3]
3. (a)(iii)Cr(OH)3 is less soluble in 0.100 moldm¯³ NaOH than it is in pure water. Explain this observation.[1]
4. (b)The value of the acid dissociation constant, Ka, of butanoic acid, CH3CH2CH2COOH, is 1.51 x 10-5 at 298 K.[2]
5. (b)(i)Calculate the pH of 0.100 moldm-3 CH3CH2CH2COOH at 298K. Show your working. pH =[2]
6. (b)(ii)Calculate the pH of 0.100 moldm¯³ NaOH at 298K. pH =[1]
7. (b)(iii)5.00 cm³ of 0.100moldm-3 NaOH is added to 10.00cm³ of 0.100 moldm-3 CH3CH2CH2COOH. Calculate the pH of the resulting solution. Show your working. pH =[2]
8. (c)80.0 cm³ of an aqueous solution containing 0.704g of CH3CH2CH2COOH is shaken with 100 cm³ of benzene, C6H6. There is 0.556 g of CH3CH2CH2COOH in the 100 cm³ of C6H6 at equilibrium. Calculate the partition coefficient, Kpc, of CH3CH2CH2COOH between C6H6 and water. Show your working. Kpc =[2]