Which is the best reagent to distinguish between propene and propyne ?
ammonical AgNO3
alkaline KMnO4
aqueous Br2
The octane number of a sample of petrol is 40 .It means that its knocking property is equal to the mixture of :
40% n-heptane + 60% iso-octane
40% petrol + 60% iso-octane
60% n-heptane + 40% iso-octane
60% petrol + 40% iso-octane
Which of the following reaction is a redox reaction ?
P2O5 + 2H2O H4P2O7
2AgNO3 + BaCl2 2AgCl + Ba(NO3)2
BaCl2 + H2SO4 BaSO4 + 2HCl
Cu + 2AgNO3 Cu(NO3)2 + 2Ag
What is 'A' in the following reaction ?
2Fe3+(aq) + Sn2+(aq) 2Fe2+(aq) + A
Sn3+(aq)
Sn4+(aq)
Sn2+(aq)
Sn
The following four solutions are kept in separate beakers and copper metal is put in each of them. Which solution will become blue after some time ?
AgNO3 solution
Zn(NO3)2 solution
Ba(NO3)2 solution
NaNO3 solution
A.
AgNO3 solution
The element, placed above in electrochemical series, can replace the elements (placed below) from their solution. Here copper is placed only above silver (Ba, Zn and Na are placed above Cu). Hence, it can replace Ag from its salt solution. Thus, solution becomes blue due to Cu2+ ions.
Cu + 2AgNO3(aq) + 2Ag
87.5% decomposition of a radioactive substance complete in 3 hours. What is the half-life of that substance ?
2 hours
3 hours
90 minutes
1 hour