Correct the ones that are wrong from the questions and answers below

1. What is the oxidation number of cobalt in the complex K3[Co(C2O4)3].3H2O?
A +6
B -6
C +3
D -3
Answer: D

2. Atoms of isotopes of the same element are identical in which of the following aspects?
A Mass number
B Number of electrons
C Sum of the number of protons and number of neutrons
D Sum of the number of electrons and number of neutrons.
Answer: A

3. On analysis of a compound it was found to contain 29.1% of sodium, 40.5% sulphur and 30.4% oxygen. What is the empirical formula of the compound?
(R.A.M: Na=23.0,016.0, S32.0)
A Na2SO4
B Na2SO3
C Na2S2O3
D NaSO4
Answer: A

4. The structural formula of the oxalate ion is given below
-0
C
C
=0
This ion is:
A Monodentate
B Tridentate
C Hexadentate
D Bidentate
Answer: D

5. Which of the following is the best description of the outermost electrons of a magnesium atom(atomic number 12)?
A Two S electrons
B Three P electrons
C Two P electrons
D One S electron
Answer: D

6. Select the reagent(s) and reaction condition(s) necessary for the conversion,
CH3
CH
Cl
A AlCl3, UV light
B Cl2, UV light
C AlCl3, reflux
D AcCl
Answer: C

7. The structure of the amino acid alanine is
CH3
|
CHNH2
|
COOH
Give the structural formula of the species formed by alanine at pH 7
A CH3
|
CHNH3+
|
COO-
B H3N+
|
CHCH3
|
COO-
C CH3
|
CHNH2
|
COO-
D H2N
|
CHCH3
|
COO-
Answer: C