PLEASEEEEE HELP ME ON QUESTION 8 ASAP!!!!!!!!!!!!!!!!!!! GIVING 20 POINTS

An unknown salt is either NaF, NaCl, or NaOCl. When 0.050 mol of the salt is dissolved in water to form 0.500 L of solution, the

victus00 [196]

Answer: The unknown salt is NaF

Explanation:

To calculate the molarity of solution, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}$

Moles of salt = 0.050 moles

Volume of solution = 0.500 L

Putting values in above equation, we get:

$\text{Molarity of salt}=\frac{0.050mol}{0.500L}\\\\\text{Molarity of salt}=0.1M$

To calculate the hydroxide ion concentration, we first calculate pOH of the solution, which is:

pH + pOH = 14

We are given:

pH = 8.08

$pOH=14-8.08=5.92$

To calculate pOH of the solution, we use the equation:

$pOH=-\log[OH^-]$

Putting values in above equation, we get:

$5.92=-\log[OH^-]$

$[OH^-]=10^{-5.92}=1.202\times 10^{-6}M$

The unknown salt given are formed by the combination of weak acid and strong acid which is NaOH

The chemical equation for the hydrolysis of $X^-$ ions follows:

$X^-(aq.)+H_2O(l)\rightleftharpoons HX(aq.)+OH^-(aq.);K_b$

Initial: 0.1

At eqllm: 0.1-x x x

Concentration of $OH^-=x=1.202\times 10^{-6}M$

The expression of $K_b$ for above equation follows:

$K_b=\frac{[OH^-][HX]}{[X^-]}$

Putting values in above expression, we get:

$K_b=\frac{(1.202\times 10^{-6})\times (1.202\times 10^{-6})}{(1-(1.202\times 10^{-6}))}\\\\K_b=1.445\times 10^{-11}M$

To calculate the acid dissociation constant for the given base dissociation constant, we use the equation:

$K_w=K_b\times K_a$

where,

$K_w$ = Ionic product of water = $10^{-14}$

$K_a$ = Acid dissociation constant

$K_b$ = Base dissociation constant = $1.445\times 10^{-11}$

Putting values in above equation, we get:

$10^{-14}=1.445\times 10^{-11}\times K_a\\\\K_a=\frac{10^{-14}}{1.445\times 10^{-11}}=6.92\times 10^{-4}$

We know that:

$K_a\text{ for HF}=6.8\times 10^{-6}$

$K_a\text{ for HCl}=1.3\times 10^{6}$

$K_a\text{ for HClO}=3.0\times 10^{-8}$

So, the calculated $K_a$ is approximately equal to the $K_a$ of HF

Hence, the unknown salt is NaF

6 0

2 years ago

Water _____.

Sergio039 [100]

Answer: is neither an acid nor a base

Explanation: Water is a universal solvent which means it can dissolve most of the substances in it.

Water has high thermal heat capacity , which means large heat is required to heat the water.

Water is not always pure as it gets contaminated by various pollutants present in the atmosphere such as gases, bacteria and suspended matter.

Water is an amphoteric substance which can act as both acid and base, thus can donate and acept [texH^+[/tex] ions.Thus it is neither an acid nor a base.

$HCl+H_2O\rightarrow H_3O^++Cl^-$

Here water is accepting a proton, thus it acts as base.

$NH_3+H_2O\rightarrow NH_4^++OH^-$

Here water is donating a proton, thus it acts as acid.

4 0

2 years ago

How does wind develop

avanturin [10]

It is caused by differences in the atmospheric pressure. When a difference in atmospheric pressure exists, air moves from the higher to the lower pressure area, resulting in winds that vary in speed. On Earth, air is also deflected by the Coriolis effect, except exactly on the equator.

8 0

3 years ago

Which atomic model proposed that electrons move in specific orbits the nucleus of an atom?

MrRa [10]

Bohr's atomic model proposed that electrons move in specific orbits around the nucleus of an atom.

3 0

2 years ago

M

vlada-n [284]

Answer:

El cocodrilo se arrastró durante 20.833 segundos.

Explanation:

El enunciado presenta omisiones y errores conceptuales. La forma correcta es la siguiente: "Un cocodrilo se arrastró 25 metros hacia la derecha con una rapidez promedio de 1.2 metros por segundo. ¿Cuántos segundos se arrastró el cocodrilo?"

Consideremos que el cocodrilo tiene un movimiento rectilíneo uniforme, el tiempo requerido para el recorrido se calcula con la siguiente ecuación cinemática:

$t = \frac{x}{v}$ (1)