5. Hydrogen cyanide has the chemical formula HCN. The compound occurs as a colourless gas or a pale blue liquid. Its solution in water is called hydrocyanic acid. It reacts with water as per the reaction below. What is the pH of 0.176 mol/L solution of the above acid (K = 4.98 x 10')? a HCN(aq) + H₂O(l) ↔ CN¯(aq) + H₂O*(aq)

5. Hydrogen cyanide has the chemical formula HCN. The compound occurs as a colourless gas or a pale blue liquid. Its solution in water is called hydrocyanic acid. It reacts with water as per the reaction below. What is the pH of 0.176 mol/L solution of the above acid (K = 4.98 x 10')? a HCN(aq) + H₂O(l) ↔ CN¯(aq) + H₂O*(aq)

Chemistry: Principles and Practice

3rd Edition

ISBN:9780534420123

Author:Daniel L. Reger, Scott R. Goode, David W. Ball, Edward Mercer

Publisher:Daniel L. Reger, Scott R. Goode, David W. Ball, Edward Mercer

Chapter16: Reactions Between Acids And Bases

Section: Chapter Questions

Problem 16.83QE

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The hydrogen phthalate ion, C8HsO4, is a weak acid with Ka = 3.91 106. C8H5O4(aq)+H2O(l)C8H4O42(aq)+H3O+(aq) What is the pH of a 0.050 M solution of potassium hydrogen phthalate. KC8H5O4? Note: To find the pH for a solution of the anion, we must take into account that the ion is amphiprotic. It can be shown that, for most cases of amphiprotic ions, the H3O+ concentration is [H3O+]=Ka1Ka2 For phthalic acid, C8H6O4 is Ka1 is 1.12 103, and Ka2 is 3.91 106.
Acrylic acid is used in the polymer industry in the production of acrylates. Its K, is 5.6 X 10“’. What is the pH of a 0.11 M solution of acrylic acid, CH2CHCOOH?
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Weak base B has a pKb of 6.78 and weak acid HA has a pKa of 5.12. a Which is the stronger base, B or A? b Which is the stronger acid, HA or BH+? c Consider the following reaction: B(aq)+HA(aq)BH+(aq)+A(aq) Based on the information about the acid/base strengths for the species in this reaction, is this reaction favored to proceed more to the right or more to the left? Why? d An aqueous solution is made in which the concentration of weak base B is one half the concentration of its acidic salt, BHCl, where BH+ is the conjugate weak add of B. Calculate the pH of the solution. e An aqueous solution is made in which the concentration of weak acid HA twice the concentration of the sodium salt of the weak acid, NaA. Calculate the pH of the solution. f Assume the conjugate pairs B/BH+ and HA/A are capable of being used as color-based end point indicators in acidbase titrations, where B is the base form indicator and BH is the acid form indicator, and HA is the acid form indicator and A is the base form indicator. Select the indicator pair that would be best to use in each of the following titrations: (1) Titration of a strong acid with a strong base. (i) B/BH+ (ii) HA/A (2) Titration of a weak base with a strong acid. (i) B/BH+ (ii) HA/A
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One half liter (500. mL) of 2.50 M HCl is mixed with 250. mL of 3.75 M HCl. Assuming the total solution volume after mixing is 750. mL, what is the concentration of hydrochloric acid in the resulting solution? What is its pH?
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Complete each of these reactions by filling in the blanks. Predict whether each reaction is product-favored or reactant-favored, and explain your reasoning. (a) _________ (aq) + Br(aq) NH3(aq) + HBr(aq) (b) CH3COOH(aq) + CN(aq) ________ (aq) + HCN(aq) (c) ________ (aq)+H2O () NH3(aq) + OH(aq)
The simplest amino acid is glycine, H2NCH2CO2H. The common feature of amino acids is that they contain the functional groups: an amine group, -NH2, and a carboxylic acid group, -CO2H. An amino acid can function as either an acid or a base. For glycine, the acid strength of the carboxyl group is about the same as that of acetic acid. CH3CO2H, and the base strength of the amino group is slightly greater than that of ammonia, NH3. (a) Write the Lewis structures of the ions that form when glycine is dissolved in 1 M HCl and in 1 M KOH. (b) Write the Lewis structure of glycine when this amino acid is dissolved in water. (Hint: Consider the relative base strengths of the -NH2 and -CO2- groups.)
8. (a) HA(aq) is a weak acid with a dissociation constant, Ka, of 8.8 x 10−12. What is the pH of a 0.022 M solution of A−(aq)? The temperature is 25 ◦C. (b) For the reaction A(g) =A(l), the equilibrium constant is 0.666 at 25.0 ◦C and 0.222 at 75.0 ◦C. Making the approximation that the entropy and enthalpy changes of this reaction do not change with temperature, at what temperature will the equilibrium constant be equal to 0.777?
A chemical system is set up by placing some solid ammonium chloride in an ammonia solution. The equilibrium established can be represented as follows: NH4*(aq) + H2O(e) 2 H30*(aq) + NH3(aq) The pH of the solution is taken, then a small amount of NaOH(aq) is added and the pH is taken again. What can be said about the change in pH for the solution? The pH significantly increases because a strong base has been added to the solution. The pH significantly decreases because a strong base has been added to the solution. There is very little change to the pH of the solution. If anything the pH of the solution decreases slightly. There is very little change to the pH of the solution. If anything the pH of the solution increases slightly.