Answer:
C.) HOCl Ka=3.5x10^-8
Explanation:
In order to a construct a buffer of pH= 7.0 we need to find the pKa values of all the acids given below
we Know that
pKa= -log(Ka)
therefore
A) pKa of HClO2 = -log(1.2 x 10^-2)
=1.9208
B) similarly PKa of HF= -log(7.2 x 1 0^-4)= 2.7644
C) pKa of HOCl= -log(3.5 x 1 0^-8)= 7.45
D) pKa of HCN = -log(4 x 1 0^-10)= 9.3979
If we consider the Henderson- Hasselbalch equation for the calculation of the pH of the buffer solution
The weak acid for making the buffer must have a pKa value near to the desired pH of the weak acid.
So, near to value, pH=7.0. , the only option is HOCl whose pKa value is 7.45.
Hence, HOCl will be chosen for buffer construction.
Answer:
An atom behaves electically neutral because it has an equal number of protons and electrons.
Explanation:
There are three sub-atomic particles: neutrons, electrons and protons. Neutrons have a neutral charge; electrons have a negative charge; and protons have a positive charge. In a regular atom, there is an equal amount of electrons and protons, making a neutral charge.
The volume of the drum after chilled quickly is 3.6 L.
<u>Explanation:</u>
As per the Charles Law, for any gas at constant pressure, volume of the gas is in direct proportion with the temperature measured in Kelvin. As the temperature increases, the gas expands and vice versa.
After chilling the drum, the volume will get reduced and it can be found as,
V2 =
=
= 3.6 L
Here the drum is chilled quickly, that is temperature is reduced and so the volume also decreases.
Answer:
97.5 km/h
Explanation:
The time taken by gino = 6 hours
Speed of Gino = 65 km/h
The expression for distance is :-
Distance = Speed x Time
So, The distance covered by Gino = 65 km/h x 6 hrs = 390 km
The same distance is covered by Lorry.
Time taken by Lorry is 2 hrs fewer than Gino = 4 hours
Speed = Distance/Time = 390 km/4 h = 97.5 km/h
<u>97.5 km/h is the average speed of Lorry for the whole journey.</u>
Explanation:
The two main categories of energy are potential energy (stored
energy) and kinetic energy (energy presently doing
work or causing change)...I hope this helps.