NTA Abhyas JEE Main2020Chemistrys Block ElementsPractice
Which of the following combination will produce H 2 gas?
Options
- AFe metal and conc. H N O 3
- BCu metal and conc. H N O 3
- CAu metal and NaCN(aq) in the presence of air
- DZn metal and NaOH(aq)
Correct answer
D. Zn metal and NaOH(aq)
Step-by-step solution
F e + c o n c . H N O 3 → P a s s i v i t y C u + c o n c . H N O 3 → N O 2 A u + N a C N + O 2 → [ A u ( C N ) 2 ] - Z n + N a O H → N a 2 Z n O 2 + H 2