The radiant energy from the sun is due to :
combustion
chemical reaction
nuclear fusion
nuclear fission
Which of the following products are formed when SiCl4 vapour are passed over hot Mg ?
SiCl2 + MgCl2
Si + MgCl2
Mg2Si + MgCl2
MgSiCl6
What is the half-life of 6C14 , if its disintegration constant is 2.31 x 10-4 yr-1 ?
0.3 x 104 yr
0.3 x 103 yr
0.3 x 108 yr
0.3 x 102 yr
Ni/Ni2+ [1.0 M] || Au3+ [1.0 M]/Au (where E° for Ni2+/Ni is -0.25 V E° for Au3+/Au is 0.150 V)
Whar is the emf of the cell ?
+ 0.4 V
- 1.75 V
+ 1.25 V
+ 1.75 V
When fluorine reacts with hot and conc. NaOH , it gives :
Na2O
Na
H2
O2
D.
O2
When fluorine reacts with hot and conc. NaOH , oxygen gas wili be evolved .
4NaOH + 2F2 4NaF + O2 + 2H2O
In acidic medium MnO42- is converted to Mn2+ .The quantity of electricity in faraday required to reduce 0.5 mole of MnO42- to Mn2+ would be :
2.5
1
5
0.5
During electrolysis of water the volume of oxygen liberated is 2.24 dm3 .The volume of hydrogen liberated , under same conditions will be :
2.24 dm3
1.12 dm3
4.48 dm3
0.56 dm3