A
Only 2
B
Neither 1 nor 2
C
Both 1 and 2
D
Only 1
Correct answer: (c) Both 1 and 2
Explanation
- A
Only 2
Only 2. The NaHCO3 formula limb is also keyed.
- B
Neither 1 nor 2
Neither. Both NCERT uses hold.
- C
Both 1 and 2
Both 1 and 2. Baking soda is sodium hydrogen carbonate (NaHCO3). It is used in soda-acid fire extinguishers.
- D
Only 1
Only 1. The extinguisher use is also keyed.
Summary. Official key is (c) both. Baking soda is NaHCO3 and it is used in fire extinguishers. Also note: Washing soda — Na2CO3·10H2O — different salt; Heat — NaHCO3 gives CO2 on heating; baking and extinguishers; Antacid — Mild; another NCERT use; Solvay — Industrial NaHCO3 / Na2CO3 route.