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The chirality of the compound
(a central carbon with Br pointing up, H on a hashed bond going back, $CH_3$ on the lower left in the plane and Cl on a wedged bond coming forward)
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is : -
(a central carbon with Br pointing up, H on a hashed bond going back, $CH_3$ on the lower left in the plane and Cl on a wedged bond coming forward)
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is : -
A
E
B
R
C
S
D
Z
Detailed Solution
E and Z are used for the geometry of double bonds, so for a chiral carbon the configuration is either R or S.
Step 1: priorities by atomic number: Br (35) > Cl (17) > $CH_3$ (C, 6) > H (1).
Step 2: the lowest priority group H is on the hashed bond, i.e. pointing away from the viewer, so the configuration can be read directly.
Step 3: trace Br (top) $\rightarrow$ Cl (lower right, in front) $\rightarrow$ $CH_3$ (lower left).
Going from the top to the lower right and then to the lower left is a clockwise path.
Clockwise with the lowest priority group pointing away means the R configuration.
So the compound has the R configuration.
Step 1: priorities by atomic number: Br (35) > Cl (17) > $CH_3$ (C, 6) > H (1).
Step 2: the lowest priority group H is on the hashed bond, i.e. pointing away from the viewer, so the configuration can be read directly.
Step 3: trace Br (top) $\rightarrow$ Cl (lower right, in front) $\rightarrow$ $CH_3$ (lower left).
Going from the top to the lower right and then to the lower left is a clockwise path.
Clockwise with the lowest priority group pointing away means the R configuration.
So the compound has the R configuration.