H2SO4 is a strong acid, but HSO4- is a weak acid
2 answers:
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<u>Answer:</u> The correct statement is if you add the soluble salt KA to a solution of HA that is at equilibrium, the pH would increase.
<u>Explanation:</u>
Common ion effect is defined as the effect which occurs on equilibrium when a common ion (an ion which is already present in the solution) is added to a solution. This effect generally decreases the solubility of a solute.
Equilibrium reaction of HA and KA follows the equation:
According to Le-Chateliers principle, if there is any change in the variables of the reaction, the equilibrium will shift in the direction in order to minimize the effect.
In the equilibrium reactions, ion is getting increased on the product side, so the equilibrium will shift in the direction to minimize this effect, which is in the direction of HA.
Thus, the addition of KA will shift the equilibrium in the left direction.
Equilibrium constant depends on the temperature of the system. It does not have any effect on any change of pH.
pH is defined as the negative logarithm of hydrogen ions present in the solution
- If the solution has high hydrogen ion concentration, then the pH will be low.
- If the solution has low hydrogen ion concentration, then the pH will be high.
As, the equilibrium is shifting in the left direction, that means concentration of ions are getting decreases. This will increase the pH of the solution.
Hence, the correct statement is if you add the soluble salt KA to a solution of HA that is at equilibrium, the pH would increase.
Answer:
Choice A: Light would acquire a blueshift.
Explanation:
When a universe collapses, clusters of stars start to move towards each other. There are two ways to explain why light from these stars will acquire a blueshift.
Stars move toward each other; Frequency increases due to Doppler's Effect.
The time period of a beam of light is the same as the time between two consecutive peaks. If
is the wavelength of the beam, and both the source and observer are static, the time period
will be the same as the time it takes for light travel the distance of one
(at the speed of light in vacuum,
).
.
Frequency is the reciprocal of time period. Therefore
.
Light travels in vacuum at a constant speed. However, in a collapsing universe, the star that emit the light keeps moving towards the observer. Let the distance between the star and the observer be when the star sent the first peak.
- Distance from the star when the first peak is sent:
.
- Time taken for the first peak to arrive:
.
The star will emit its second peak after a time of. Meanwhile, the distance between the star and the observer keeps decreasing. Let be the speed at which the star approaches the observer. The star will travel a distance of
before sending the second peak.
- Distance from the star when the second peak is sent:
.
- Time taken for the second peak to arrive:
.
The period of the light is when emitted from the star. However, the period will appear to be shorter than
for the observer. The time period will appear to be:
.
The apparent time period is smaller than the initial time period,
. Again, the frequency of a beam of light is inversely proportional to its period. A smaller time period means a higher frequency. Colors at the high-frequency end of the visible spectrum are blue and violet. The color of the beam of light will shift towards the blue end of the spectrum when observed than when emitted. In other words, a collapsing universe will cause a blueshift on light from distant stars.
The Space Fabric Shrinks; Wavelength decreases as the space is compressed.
When the universe collapses, one possibility is that clusters of stars move towards each other. Alternatively, the space fabric might shrink, which will also bring the clusters toward each other.
It takes time for light from a distant cluster to reach an observer on the ground. The space fabric keeps shrinking while the beam of light makes its way through the space. The wavelength of the beam will shrink at the same rate. The wavelength of the beam of light will be shorter by the time the beam arrives at its destination.
Colors at the short-wavelength end of the visible spectrum are blue and violet. Again, the color of the light will shift towards the blue end of the spectrum. The conclusion will be the same: a collapsing universe will cause a blueshift on light from distant stars.