7-OXIDATION, REDUCTION, RED-OX REACTIONS, TYPES

Size: px

Start display at page:

Download "7-OXIDATION, REDUCTION, RED-OX REACTIONS, TYPES"

Erick Logan
5 years ago
Views:

1 7-OXIDATION, REDUCTION, RED-OX REACTIONS, TYPES 1) In the reaction CuO + NH Cu + N + HO, the oxidation number of N changes from 1) to 0 ) 0 to + ) to + 4) to 0 ) In the reaction MnO 4 MnO, the number of OH ions involved in the balanced equation is 1) 4 ) 6 ) 4) + + ) In the reaction CrO 7 + NO + H Cr + NO + HO the stoichiometric coefficients of CrO 7, NO & H + respectively are 1) 1,, 8 ) 1, 4, 8 ) 1,, 1 4) 1, 15, 1 + 4) In the reaction NO + HO NO + H + ne, the value of n is 1) 4 ) ) 4) 1 5) Oxidation state of iron is zero in the complex K Fe CN Fe H O SO 1) 4 ( ) 6 ) ( ) 5 4 ) Fe( CO) 5 4) Na Fe ( CN ) 6 6) In which of the following pair of species, the central atom exhibits same oxidation state 1) SO,SO ) CrO,CrO ) MnO,MnO 4) Cr O, Cr O ) In the reaction MnO4 + CO4 + H Mn + CO + HO the coefficients of + MnO 4, CO 4, Mn & CO are respectively 1) 1, 5,1,10 ), 5,,10 ),,,6 4) 1, 6,1,1 8) The element which exhibits only one oxidation state in its compounds is 1) Cs ) Cl ) P 4) Mn 9) The number of electrons required to balance the following half reaction in basic medium is Cl ClO. 1) 6 ) 8 ) 10 4) 1 xcr OH + yho + zoh acro + bho. The coefficients x, y & z in the above equation 10) ( ) 4 are 1) 1,, ),, ),, 4 4),, 4 11) Which is not redox reaction among the following? 1) Cl+ KI KCl + I ) KClO KCl + O ) H+ Cl HCl 4) KCrO 7 + KOH KCrO4+ HO

2 1) Match the following underlined elements with oxidation numbers LIST I LIST II A) HCN 1) + 7 B) ClF ) + 6 C) HNO 4 ) + 5 D) CrO 5 4) + Correct match is A B C D 1) 5 1 ) ) 5 4 4) 1 4 5) + 1) Which of the following is correct I) Oxidants reduce themselves II) Reduction involve de electronation III) Reductants oxidise others Correct combination is 1) All are correct ) I and II are correct ) II and III are correct 4) I and III are correct 14) The oxidation number of sodium in Na Hg is 1) + 1 ) + ) + 4) Zero 15) Oxidation numbers of nitrogen in Ammonium nitrite are respectively 1) +, + 5 ), + ) + 5, - 4) +, ) Oxidation number of nitrogen in Ammonium nitrate are respectively 1) +, +5 ), + ), +5 4) +, ) In which of the following hydrogen exhibits negative oxidation state 1) NH ) H S ) C 6 H 6 4) CaH 18) The strong reducing agent is 1) HNO ) H S ) H SO 4) SnCl

3 19) In the reaction Zn + HSO4 ZnSO 4+ H 1) Zn is oxidised in H SO 4 ) Hydrogen is oxidised in H SO 4 ) Sulphur undergoes reduction in H SO 4 4) Sulphur undergoes oxidation in H SO 4 0) When Zn is added to CuSO 4 solution, Cu is precipitated. It involves 1) Oxidation of Cu + ) Reduction of Cu + ) Zn is reduced, Cu is oxidised 4) There is neither oxidation nor reduction 1) Manganate ion is changed to permanganate ion. It is an example of 1) Oxidation ) Reduction ) Neither oxidation nor reduction 4) Disproportionation ) Chlorine gas is passed through hot solution of caustic potash then chlorine in the reaction undergoes 1) Oxidation ) Reduction ) Oxidation & Reduction 4) Neither oxidation nor reduction + + ) MnO4 + H + S Mn + HO + S, the number of electrons involved during the above transformation 1) 8 ) 6 ) 10 4) 5 4) The number of moles of oxalate ions oxidised by one mole of MnO 4 ion is 1) 5 ) 5 ) 1 5 4) 5 5) For the redox reaction ( ) Cr OH + OH + IO CrO + H O + I. The correct coefficients of the 4 reactants for the balanced equation are respectively 1) 1, 5, 1 ), 4, 1 ) 1,, 1 4), 6, 6) List I List II P H PO I) electrons are involved A) 4 B) CrO CrO II) 6 electrons are involved 4 5 C) IO I III) 4 electrons are involved D) Cl ClO IV) 10 electrons are involved V) No electrons are involved The correct match is 1) A III, B V, C II, D IV ) A IV, B I, C V, D II ) A I, B II, C III, D IV 4) A II, B III, C IV, D V

4 OH 7) Cr Cr ( OH) 4 for the balanced oxidation half reaction the number of electrons and OH - ions required respectively 1) 4, 4 ) 4, ), 4 4), 8) The oxidation number of iron in the brown ring complex is 1) + ) + ) + 4 4) +1 a KMnO + b H SO + c FeSO K SO + MnSO + Fe SO + H O. In this un balanced 9) ( ) stoichiometric equation, the values of a, b and c are respectively 1), 8 and 10 ) 1, 4 and 10 ), 10 and 8 4), 8 and 16 0) The number of moles of FeSO4 In balanced equation of KCrO 7 + HSO4+ FeSO4 KSO4+ Cr( SO4) + Fe( SO4) + H O is 1) 1 ) 7 ) 6 4) + + 1) In the equation MnO4 + CO4 + H Mn + CO the numbers of moles of H+ ions involved in the balanced equation are 1) 9 ) 16 ) 6 4) 1 ) In the reaction, Cl + OH C l + OCl the number of moles of OH ions involved in the above equation is 1) ) ) 4 4) 5 ) In the equation pnh+ qo rho + s NO, the stoichometric coefficient of which species is 4. I) NH II) O III) H O IV) NO The correct answer is 1) I, II and III ) I and IV ) II, III and IV 4) II and III 4) Assertion: (A): The oxidation state of Iron in Fe O 4 is + Reason: (R): Fe always shows + in all its compounds. 1) Both A and R are true, R is correct explanation of A. ) Both A and R are true, R is not the correct explanation of A. ) A is true but R is false 4) both A and R are false 5) In the conversion of BaO to BaO, the oxidation number of 1) Barium increases ) Oxygen increases ) Oxygen decreases 4) Barium decreases 6. Oxidation state of Ni in Ni (CO)4 is 1) 0 ) 4 ) 8 4 )

5 7. Oxidation state of Fe in K4[Fe(CN)6] 1) +6 ) +4 ) + 4) In which of the following the oxidation state of chlorine is +5? 1) HClO4 ) HClO ) HClO 4) HCl 9. All elements commonly exhibit an oxidation state of 1) +1 ) 1 ) zero 4) The maximum oxidaton state that fluorine exhibits is 1) 1 ) zero ) +1 4) The element that always exhibits a negative oxidation state in its compounds is 1) Nitrogen ) Oxygen ) Fluorine 4) Chlorine 4) The oxidation number of Nitrogen is fractional in 1) NH ) N H ) N H 4 4) NH OH KEY 1)4 )1 ) 1 4) 4 5) 6) 7) 8) 1 9) 10) 11)4 1) 1) 14)4 15) 16) 17)4 18) 19) 1 0) 1) 1 ) ) 4)4 5) 6)1 7) 8) 4 9) 1 0) 1) )1 ) 4)4 5) 6) 1 7) 8) 9) 40) 41) 4) HINTS 1. In NH oxidation state of N is x+=0, x=- In elementary state ox, no is zero. MnO4 MnO, Balancing oxygen MnO - 4 MnO +H O Balancing H; MnO H O MnO +H O +4OH - - Balancing charge : MnO 4 +H O +e MnO +4OH -. The stoichiometric equation is Cr O + NO + 8H Cr + NO + 4H O NO + H O NO + H + ne, 4. Total charge in reactants side=0 Total charge in products side=-1+ =+1. Hence n=1

6 5. Ox.state of metal in metal carbonyl is zero. 6. O.s of Cr in CrO - 4 is x+4(-)=-, x=+6 In CrO 5, one normal and 4 peroxy oxygen atoms are present. X+4(-1)+(-)=0,x=+6 7. Balanced equation is MnO + 5C O + 16H Mn + 10CO + 8H O Elements of IA always show +1 in their compounds Cl ClO - Balancing oxygen Cl + 6H O ClO Balancing H; Cl + 6H O+1OH - ClO - +1H O Balancing charge: Cl + 1OH - +10e ClO - +6H O 10. Balanced equation is ( ) xcr OH + HO + 4OH CrO + 8HO Ox.S of Cr is same (+6) in both sides. 1. in HNO 4,two peroxy O atoms present. +1 +X+(-)+(-1)=0,X= O.S of metal in an alloy is zero. 15. NH 4 NO contains NH + 4 and NO - ions. In NH + 4 O.S of N is - and in NO - is NH 4 NO contains NH + 4 and NO - ions. In NH + 4 O.S of N is - and in NO - is H shows +ve oxidation state in metallic hydrides. 18. As S is in its lowest oxidation state. 19. O.S of Zn increases from 0 to O.S of Cu decreases from + to O.S of Mn increases from +6 to NaOH+ Cl 5NaCl+NaClO +H O, O.S of changes from 0 to -1 and 0 to MnO + 16H + 5S Mn + 8H O + 5S 4 Mn gains 10e and S - looses 10e 4. KMnO4 + 5HCO4 + HSO4 KSO4 + MnSO4 + 10CO +8 HO As per equation moles KMnO 4 oxidises 5 moles of Oxallic acid. 1mole KMnO 4 oxidises 5/ moles of Oxallic acid K Cr O + H SO + FeSO K SO + Cr SO + Fe SO + H O 5. ( ) ( ) Cr (OH) + 4OH + IO I + CrO HO 7. Cr [ Cr(OH) 4 ] Balance oxygen atoms Balance hydrogen atoms ( ) Cr + 4H O Cr OH 4 ( ) Cr + 4HO + 4OH Cr OH 4H 4 + O

7 Balance the charge Cr 4H O 4OH ( ) + + Cr OH + 4HO + e 4 8: The brown ring complex compound is [Fe (HO)5 NO] SO4. The complex ion is [Fe (HO)5 NO]+ Oxidation numbers of HO is zero and NO is+1. Oxidation state of Fe is +1 KMnO + 8 H SO + 10 FeSO K SO + MnSO + 5Fe SO + 8H O 9. Balanced equation is ( ) Balanced equation is ( ) ( ) K Cr O + 7H SO + 6FeSO K SO + Cr SO + Fe SO + 7H O MnO4 + 5CO4 + 16H Mn + 10CO + 8HO 1.. Cl + OH - Cl - + ClO - +H O. 4NH+ 5O 6HO + 4 NO 4. Fe O 4 is a mixed oxide of FeO and Fe O. Thus Fe shows + and + OX.States 5. OX.ST of oxygen decreases from -1 to -.

Redox Worksheet 1: Numbers & Balancing Reactions

Name: Date: Per: Redox Worksheet 1: Numbers & Balancing Reactions Assigning Oxidation Number rules: Elements and Compounds have an oxidation number/total of 0 Group I and II In addition to the elemental