Answer:
a) ethanol is dehydrated by concentrated sulphuric acid to yield ethene
b) Concentrated phosphoric(V) acid, H3PO4, can be used instead of sulphuric acid
Explanation:
Ethene is prepared in the lab by heating ethanol with concentrated sulphuric acid at 170°C. The mixture contains 1:2 volume ratio of the ethanol and concentrated acid. Ethylhydrogentetraoxosulphate VI is first formed and then decomposes to yield ethene and sulphuric acid.
The overall reaction is akin to the dehydration of ethanol. As is easily seen above; this is a two stage reaction. The first stage is the formation of the ester, the second stage involves the dehydration of the ester to yield ethene. The ethene gas is passed through concentrated sodium hydroxide to remove any gaseous impurities present and then it is collected over water.
Concentrated phosphoric(V) acid, H3PO4, can be used instead of concentrated sulphuric acid as a dehydrating agent in the laboratory preparation of ethene.
Answer:
393 cm
Explanation:
Step 1: Given and required data
- Density of liquid methylene bromide (ρ): 2.50 g/mL (2.50 g/cm³)
- Earth's gravity (g): 9.81 m/s²
- Atmospheric pressure (P): 0.950 atm
Step 2: Convert 0.950 atm to Pa (N/m²)
We will use the conversion factor 1 atm = 101325 Pa.
0.950 atm × 101325 Pa/1 atm = 9.63 × 10⁴ Pa
Step 3: Convert 2.50 g/cm³ to kg/m³
We will use the conversion factors:

Step 4: Calculate the height (h) of the liquid column
We will use the following expression.
P = ρ × g × h
h = P / ρ × g
h = 9.63 × 10⁴ Pa / (2.50 × 10³ kg/m³) × 9.81 m/s²
h = 3.93 m = 393 cm
Answer:
where is the chosices to choose from
Explanation:
Answer:
A.), as it will decrease.