The solutions of $0.1\ \text{mol dm}^{-3}\ \text{Mg(NO}_3)_2$ and $0.1\ \text{mol dm}^{-3}\ \text{Ba(NO}_3)_2$ are each treated separately in a sequence of reactions with pure reagents. M, N and P are magnesium compounds. Q, R and S are barium compounds. How many of M, N, P, Q, R and S are white precipitates?
- A2
- B3
- C4
- D5