BaSO₄ is relatively harmless, but BaS is highly toxic.
BaSO₄ is quite insoluble (240 µg/100 mL). It is a <em>mild irritant</em> in cases of skin contact and inhalation. However, it is <em>safe enough</em> that health professionals ask patients to drink a suspension of BaSO₄. The Ba is opaque to X-rays, so it makes the stomach and intestines more visible to radiographers.
BaS is soluble (7.7 g/100 mL). It reacts slowly with water and more rapidly in the acid conditions of the stomach to <em>release H₂S</em>.
BaS + 2HCl ⟶ BaCl₂ + H₂S
An H₂S concentration of 60 mg/100 mL can be <em>fatal within 30 min</em>.
<em>Don’t eat barium sulfide!</em>
Cellar respiration simple if u need explanation just search up
Answer:
(a) Density of the air = 1.204 kg/m3
(b) Pressure = 93772 Pa or 0.703 mmHg
(c) Force needed to open the door = 15106 N
Explanation:
(a) The density of the air at 22 deg C and 1 atm can be calculated using the Ideal Gas Law:

First, we change the units of P to Pa and T to deg K:

Then we have

(b) To calculate the change in pressure, we use again the Ideal Gas law, expressed in another way:

(c) To calculate the force needed to open we have to multiply the difference of pressure between the inside of the freezer and the outside and the surface of the door. We also take into account that Pa = N/m2.

The awnser to your question would be B