Practice Exams ChE - 18

1. A uniform current deposits 0.6332 grams of Ag in 90 minutes. The 45.2 mL volume of H2 at 25 degC and 740 mm measured over water it would liberate in 60 minutes is
a. 50.8 mL
b. 60.2 mL
c. 30.5 mL
d. 45.2 mL
e. None of the above

2. A compound has the following percent composition: Na-19.3%, S-26.9%, O-53.8%. Its molecular mass is 238. Derive its molecular formula.
a. NaSO4
b. Na2SO4
c. Na2S2O8
d. Na2SO3
e. NaSO3

3. In the flow processes, neglecting KE and PE changes, the expansion -? PV represents
a. heat transfer
b. shaft work
c. closed system work
d. enthalpy change
e. none of the above

4. If 0.680 gram of an unknown acid, H2B, required 25 mL of 0.125 N NaOH, the equivalent weight of the acid is
a. 229.8
b. 459.6
c. 435.2
d. 217.6
e. 333

5. From which of the given alkanes should be easiest to prepare a single pure monochloro product?
a. n-butane
b. isobutene
c. n-hexane
d. cyclohexane
e. isohexane

6. Thermolar solubility of salt AB2 with Ksp = 10^-12 is
a. 6.29 x 10^–5
b. 1 x 10^–4
c. 3.16 x 10^ –4
d. 7.93 x 10^–5
e. 2 x 10^–3

7. A 0.2 molal solution of KCl freezes at –0.680 degC. The osmotic P at 0 degC is
a. 7.3 atm
b. 6.5 atm
c. 8.2 atm
d. 5.6 atm
e. none of the above

8. Which of the following aqueous salt solution will have a pH below neutral value?
a. NaACO
b. Na2CO3
c. Na2S
d. KCl
e. none of the above

9. For HOAc, the melting point at 1 atm is 16.61 degC. Delta Hf = 2800 cal/mol, Delta Vf = 9.614 cal/mol. What is the melting point at 11 atm?
a. 16.61 degC
b. 17.24 degC
c. 9.02 degC
d. 16.85 degC
e. none of the above

10. In following pair of elements, the pair belonging to metalloids is
a. B and C
b. Ca and Mg
c. P and S
d. As and Te
e. K and Sr