Aqua-regia is obtained by mixing two different acids in the ratio :
1HNO3: 3HCl
2HNO3: 2HCl
1HNO3: 2HCl
3HNO3: 1HCl
Which one of the following electrolytes is used in Down's process of extracting sodium metal?
NaCl + KCl + KF
NaCl
NaOH + KCl +KF
NaCl + NaOH
A.
NaCl + KCl + KF
Sodium metal is manufactured by the electrolysis of fused sodium chloride rruxed with KCl and KF.
On electrolysis
At iron cathode
Na+ + e- → Na(s) (metallic sodium)
At grapite anode
2Cl- → 2Cl2(g) + 2e-
NaCl melts at 800°C It is difficult to attain and maintain its melting point So, KCl and KF are mixed to lower the melting point of NaCl to about 600°C. KCl and KF are themselves not electrolysed under the voltage conditions used for sodium.
What is the reaction occurring at the anode in Down's process for the extraction of sodium?
4OH- → 2H2O + O2 + 4e-
Na+ + e- → Na
2Cl- → Cl2 + 2e-
NaOH → Na+ + OH-
When bauxite powder is mixed with coke and reacted with nitrogen at 2075 K, carbon monoxide and X are formed. What is the gas formed when X is reacted with water?
NH3
N2
N2O
O2
Observe the following statements regarding purification of bauxite
I. During Hall's process, silica is removed as Si (vapour).
II. Bauxite ore contaminated with Fe2O3 is purified in Baeyer's process.
III. During Serpeck's process, AlN is formed.
The correct answeris
I, II and III are correct
Only I and II are correct
Only I and III are correct
Only II and III are correct
Match the following-
List - I | List - II |
A. Feldspar | i. [Ag3SbS3] |
B. Asbestos | ii. Al2O3.H2O |
C. Pyragyrite | iii. MgSO4.H2O |
D. Diaspore |
iv. KAlSi3O8 v. CaMg3(SiO3)4 |
The correct answer is-
A - iv; B - v; C - ii; D - i
A - iv; B - v; C - i; D - ii
A - iv; B - i; C - iii; D - ii
A - ii; B - v; C - iv; D - i