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WORKSHEET 3G COMPOUNDS

1. In a polyatomic ion, the algebraic sum of the oxidation numbers of all atoms is equal to
A) 0
B) 10
C) The number of atoms in the ion.
D) The charge of the ion.

2. What is the oxidation number of hydrogen in most compounds?
A) –1
B) 0
C) +1
D) It is equal to the algebraic sum of the oxidation numbers of the nonmetals.

3. What is the oxidation number of oxygen in H2O2?
A) –2 B) +2 C) –1 D) +4

4. What is the oxidation number of magnesium in MgO?
A) –1 B) +1 C) 0 D) +2

5. What is the oxidation number of sulfur in H2SO4?
A) –2 B) +4 C) 0 D)+6

6. In which of the following compounds N atom has an oxidation number of +4 ?
A) NO B) NO2 C) N2O D) NH3


7. What is the oxidation number of sulfur in sulfate ion?
A) +2 B) +8 C) +6 D) +9

8. What is the oxidation number of carbon in CaCO3?
A) +6 B) +4 C) +2 D) 0

9. I. K2Cr2O7 II. Cr2O3 III. K2CrO4
What would you expect to be correct order of increasing oxidation number of Cr atoms?
A) I=III>II B) I>II=III C) III>I=II D) I>II>III


10. What is the oxidation number of carbon in oxalate ion?
A) +8 B) +6 C) +4 D) +3


11. What are the oxidation numbers of nitrogen in NH4NO3 in order?
A) -3 and +5 B) -4 and -6
C) -3 and -3 D) +4 and +6



12. X is in 2A group in periodic table. What is the formula of the compound formed from X and nitrate ion?
A) X(NO3)2 B) X2NO3 C) XNO3 D) X3(NO)2

13. In most compounds X has +1 and +2 as oxidation number. Which one of the followings is not expected to be chemical formula of X?
A) X2O B) XSO4 C) XNO3 D) XOH

14. Which one of the following Mn has a different oxidation number?
A) MnSO4B) MnO C) MnCl2 D) MnO2


15. What is the oxidation number of S in (NH4)2SO4?
A) –2 B)+1 C) +2 D)+6


16. What are the oxidation numbers of X,Y and Z elements respectively in Mg3(XO3)2, Na2YO4 and K2ZO4?
X Y Z
A) +3 +6 +6
B) +5 +7 +7
C) +3 +6 +7
D) +5 +6 +6


17. I. H3BO3 II. H3PO4 III. P2O3 IV. K3P
Which phosphorous atoms in the following pairs have the same oxidation numbers?
A) I-IIB) III-IV C) I-III D) II-IV


18. What is the oxidation number of manganese in KMnO4?
A) +1 B) +5 C) +7 D) +8


19. Which of the following is correct name for NH4OH?
A) Ammonium hydroxide
B) Ammonium (I) hydroxide
C) Ammonium monoxide
D) Nitrogen monoxide



20. What is the formula of Iron (II) carbonate?
A) Fe2(CO3)2 B) Fe2(CO)2 C) FeCO3 D) F2CO3