Q8.what happened to the mixture?

The pH of a 0.78M solution of 4-pyridinecarboxylic acid HC6H4NO2is measured to be 2.53.Calculate the acid dissociation constant

nika2105 [10]

Answer : The value of acid dissociation constant is, $1.1\times 10^{-5}$

Solution : Given,

Concentration pyridinecarboxylic acid = 0.78 M

pH = 2.53

First we have to calculate the hydrogen ion concentration.

$pH=-\log [H^+]$

$2.53=-\log [H^+]$

$[H^+]=2.95\times 106{-3}M$

Now we have to calculate the acid dissociation constant.

The equilibrium reaction for dissociation of (weak acid) is,

$HC_6H_4NO_2\rightleftharpoons C_6H_4NO_2^-+H^+$

initially conc. 0.78 0 0

At eqm. (0.78-x) x x

The expression of acid dissociation constant for acid is:

$k_a=\frac{[C_6H_4NO_2^-][H^+]}{[C_6H_4NO_2]}$

As, $[H^+]=[C_6H_4NO_2^-]=x$

So, $x=2.95\times 106{-3}M$

Now put all the given values in this formula ,we get:

$k_a=\frac{(x)\times (x)}{(0.78-x)}$

$k_a=\frac{(2.95\times 106{-3})\times (2.95\times 106{-3})}{(0.78-2.95\times 106{-3})}$

$K_a=1.1\times 10^{-5}$

Therefore, the value of acid dissociation constant is, $1.1\times 10^{-5}$

7 0

4 years ago

Using the SDS, write the major hazard of concentrated HCL

shusha [124]

Answer:

According to the Safety Data Sheet (SDS), the major harzard of concentrated HCl is that it may cause severe burns to skin, eyes and mucous membranes.

Explanation:

The SDS also informs that:

Most Important Hazards:

May cause severe burns to skin, eyes and mucous membranes.

 Steam produced is irritating.

 Pollution of rivers and water bodies by changing the pH. Affects flora and fauna that comes in contact with acid.

Product Effects:

 If in direct contact with eyes will cause serious burns and vision loss.

Adverse effects to human health:

 Inhalation causes severe respiratory tract irritation. May cause pulmonary edema. The contact with the skin causes burns, which can lead to dermatitis. Prolonged contact of acid leads to visual damage to vision loss. If swallowed, may cause burns to the mucous membranes of the mouth and digestive system.

Environmental Effects:

 Affects rivers and streams by changing the pH of the water. May contaminate the soil. Vapors may temporarily affect air quality.

Physical and chemical hazards:

 Reacts with metals such as; iron, aluminum, zinc, magnesium, among others, forming hydrogen, which mixed with air may cause explosion and air displacement upon ignition under specific.

4 0

4 years ago

Given 1kg=2.20 lbs, how many kilograms are in 125 lbs?<br> (Metric conversion)

Nadya [2.5K]

Answer:

56.82 Kg

Explanation:

Given data:

1 Kg = 2.20 lbs

Number of kilogram in 125 lbs = ?

Solution:

lbs is used for pound. lb is abbreviation of libra. It is Latin word meaning balance.

Both kilogram and pounds are units of mass. Pound is smaller unit than kilogram.

one Kg = 2.20 lbs

Number of kg in 125 lbs:

125 lbs × 1 Kg/2.20 lbs

125 lbs.Kg/2.20 lbs

56.82 Kg

7 0

4 years ago

If a chemical reaction produces 20.0 grams of product, but by stoichiometry it is supposed to have 25.0 grams of product; what i

djyliett [7]

Answer:

d

Explanation:

d

3 0

2 years ago

How to name Mg3(PO3)2•9H20

eimsori [14]

Magnesium phosphite maybe

5 0

3 years ago