MCQ
Which of the following is a combination reaction?
- A$2\mathrm{NaHCO}_3(\mathrm{~s}) \rightarrow \mathrm{Na}_2 \mathrm{CO}_3(\mathrm{~s})+\mathrm{CO}_2(\mathrm{~g})+\mathrm{H}_2 \mathrm{O}(\ell)$
- ✓$\mathrm{C}+\mathrm{O} 2 \rightarrow \mathrm{CO} 2$
- C$\left(\mathrm{NH}_4\right)_2 \mathrm{Cr}_2 \mathrm{O}_7 \rightarrow \mathrm{Cr}_2 \mathrm{O}_3+4 \mathrm{H}_2 \mathrm{O}+\mathrm{N}_2$
- D$\mathrm{NaCl}+\mathrm{AgNO}_3 \rightarrow \mathrm{AgCl}+\mathrm{NaNO}_3$