Q.1
In which reaction below, the oxidation number of nitrogen changes from +5 to +2?
  • $Cu+4HNO_3\longrightarrow Cu\left(NO_3\right)_{2\ }+2NO+2H_2O$
  • $2NO+O_2\longrightarrow2NO_{2\ }$ ​
  • $N_2+3Mg\longrightarrow Mg_3N_2$
  • $4NH_3+5O_2\longrightarrow4NO+6H_2O$
Q.2
Which one below is BOTH oxidising agent and reducing agent?
  • NaNaNa
  • $SO_{2\ }$ ​
  • $Cl_{2\ }$ ​
  • $CO_{2\ }$ ​
Q.3
Which compound has manganese with oxidation number +6?
  • K2MnO4K_2MnO_4K2​MnO4​
  • KMnO4KMnO_4KMnO4​
  • $MnO_{2\ }$ ​
  • $MnCl_{2\ }$ ​
Q.4
An element in a compound turns into an element in a chemical reaction. The element ...
  • is definitely oxidised
  • is definitely reduced
  • may have been oxidisied or reduced
  • is neither oxidised nor reduced
Q.5
What is the colour change of acidified KMnO4(aq) solution when serving as oxidizing agent?
  • From green to orange
  • From orange to green
  • From purple to blue
  • From colourless to purple
Q.6
What is the reducing agent of this reaction?3Mg + N2−−−−> Mg3N2
  • Mg
  • N2
  • Mg3N2
  • MgN
Q.7
What is the oxidizing agent of this reaction?3Mg + N2−−−−> Mg3N2
  • Mg
  • N2
  • Mg3N2
  • MgN
Q.8
What is the species that gain electrons in a redox reaction?
  • oxidizing agent
  • reducing agent
  • is oxidized
  • increases in oxidation number
Q.9
What is oxidation number of O in O2 ?
  • 0
  • -2
  • +1
  • +2
Q.10
The sum of the oxidation numbers in SCN- is equivalent to
  • 0
  • -1
  • +1
  • +3
0 h : 0 m : 1 s