Sure, let's go through the problem step-by-step to understand how we determine the formula of the metal phosphide given that the chloride of the metal [tex]\( M \)[/tex] is [tex]\( MCl_3 \)[/tex].
1. Identify the charge on metal [tex]\( M \)[/tex] in [tex]\( MCl_3 \)[/tex]:
- Since [tex]\( MCl_3 \)[/tex] indicates that one metal [tex]\( M \)[/tex] is combined with three chlorine atoms, and each chlorine carries a [tex]\(-1\)[/tex] charge, the overall charge from the chlorines is [tex]\( 3 \times (-1) = -3 \)[/tex].
- To balance this, the metal [tex]\( M \)[/tex] must have a +3 charge, resulting in [tex]\( M^{3+} \)[/tex].
2. Determine the charge on phosphide:
- The phosphide ion, denoted as [tex]\( P \)[/tex], typically has a [tex]\(-3\)[/tex] charge, resulting in [tex]\( P^{3-} \)[/tex].
3. Formulate the metal phosphide compound:
- For a stable compound between metal [tex]\( M \)[/tex] with a [tex]\( +3 \)[/tex] charge and phosphide with a [tex]\( -3 \)[/tex] charge, the charges must balance out.
- Since [tex]\( M \)[/tex] has a [tex]\( +3 \)[/tex] charge and [tex]\( P \)[/tex] has a [tex]\( -3 \)[/tex] charge, the formula for the compound is formed by combining one [tex]\( M \)[/tex] with one [tex]\( P \)[/tex].
Thus, the formula for the metal phosphide compound is [tex]\( MP \)[/tex].
The correct answer is therefore:
(B) [tex]\( MP \)[/tex].
