The correct answer is option B, that is, the pitch changes from low to high.
The Doppler shift or the Doppler Effect refers to the variation in the wavelength or frequency of a wave in association with an observer who is traveling comparative to the source of the wave. A prime illustration of Doppler shift is the modification of the pitch heard when a vehicle sounding a horn comes towards and move away from an observer.
In comparison to the frequency emitted, the obtained frequency is greater at the time of approach, similar at the instant of passing by, and lower at the time of recession.
Assume 1 tsp is approximately can hold 5 mL liquid.
Given the dose of medicine = 1.5 tsp
Converting 1.5 tsp to mL:
= 7.5 mL
Given the specific gravity of the medicine = 1.23
That means density of the medicine with respect to water will be 1.23
As the density of water is 1 g/mL
We can take density of the medicine to be 1.23 g/mL
Calculating the mass of medicine in grams:

9.225 g medicine is present in one dose.
%yield = 54.6%
<h3>Further explanation</h3>
Percent yield is the compare of the amount of product obtained from a reaction with the amount you calculated
(theoretical)
General formula:
Percent yield = (Actual yield / theoretical yield )x 100%
<h3 />
Reaction
2ZnS+3O₂ ⇒ 2ZnO+2SO₂
MW ZnS = 97.474 g/mol

MW ZnO = 81.38 g/mol
- mol ZnO (from mol ZnS as limiting reactant, O₂ excess)


Theoretical production = 125.388

CL- is Chloride, so your answer would be C.Chloride.