How many mL of a 1.00 M HCl solution would need to be added to 100 mL of 0.263 M ammonia to produce a buffer with a pH of 10.00. The pKa of ammonia is 9.25.

3.97mL of 1.00M HCl must be added

Explanation:

The buffer of ammonia and ammonium ion follows the equation:

pH = pKa + log [NH₃] / [NH₄⁺] (1)

Where pH is the pH we want to obtain: 10.00

pKa is the pKa of the buffer: 9.25

[NH₃] could be taken as moles of ammonia

And NH₄⁺ moles of ammonium ion

When NH₃ reacts with HCl:

NH₃ + HCl → NH₄⁺ + Cl⁻

NH₄⁺ is produced. That means moles of ammonia are Initial moles of ammonia - Moles of HCl added

Moles of HCl added = Moles of ammonium ion

The total moles of the buffer are:

0.100L * (0.263mol / L) = 0.0263moles = [NH₄⁺] + [NH₃] (2)

Rewriting (1):

10.00 = 9.25 + log [NH₃] / [NH₄⁺]

0.75 = log [NH₃] / [NH₄⁺]

Replacing (2) in (1):

0.75 = log 0.0263 -  [NH₄⁺] / [NH₄⁺]

5.6234 = 0.0263 -  [NH₄⁺] / [NH₄⁺]

5.6234[NH₄⁺] = 0.0263 - [NH₄⁺]

6.6234[NH₄⁺] = 0.0263

[NH₄⁺] = 0.00397 moles = Moles HCl

To obtain these moles we must add:

0.00397 moles HCl * (1L / mol) = 0.00397L =

3.97mL of 1.00M HCl must be added

the reaction mixture contains some ammonia, plus a lot of unreacted nitrogen and hydrogen. the mixture is cooled and compressed, causing the ammonia gas to condense into a liquid. the liquefied ammonia is separated and removed. the unreacted nitrogen and hydrogen are then recycled back into the reactor .

a mercury barometer is a device that uses the physical properties of mercury in a tube to measure barometric pressure. mercury barometers are used for : -

1. measurement of atmospheric pressure  

2. determining the altitude of a place

3. weather forecasting

4. calibration and checking of aneroid barometers

5. application in fluid mechanics

6. measurement of pressure in aircrafts

7. surface weather analysis

8. preparation of barographs

9. usage in physical sciences like physics, astronomy & chemistry

10. preparation of aircraft altimeters

characteristics of mercury barometer : -

1.used to define and measure atmospheric pressure.

2.on the average at sea level the column of mercury rises to a height of about 760 mm.

3.this quantity is equal to 1 atmosphere.

4.it is also known as standard atmospheric pressure.

5.a barometer in which the weight of a column of mercury in a glass tube with a sealed top is balanced against that of the atmosphere pressing on an exposed cistern of mercury at the base of the mercury column, the height of the column varying with atmospheric pressure.