Acids, Bases, and Salts Quiz

Sour

Red

Blue

<p>Turmeric</p> Signup and view all the answers

<p>Purple</p> Signup and view all the answers

<p>Lichen</p> Signup and view all the answers

<p>Indicators</p> Signup and view all the answers

<p>Methyl orange or phenolphthalein</p> Signup and view all the answers

<p>It turns reddish-brown</p> Signup and view all the answers

<p>Distilled water is devoid of any ionic compounds, while rain water dissolves atmospheric gases, such as carbon dioxide, which form ions allowing it to conduct electricity.</p> Signup and view all the answers

<p>CaCO3(s) + 2HCl(aq) -&gt; CaCl2(aq) + H2O(l) + CO2(g)</p> Signup and view all the answers

<p>An increase in the concentration of $H^{+}$(aq) ions makes the solution more acidic, while a decrease in the concentration of $H^{+}$(aq) ions makes the solution more basic.</p> Signup and view all the answers

<p>Solution A has more hydrogen ion concentration and it is acidic. Solution B is basic.</p> Signup and view all the answers

<p>If the soil is too acidic, a farmer would treat it with quick lime, slaked lime, or chalk to neutralize the excess acidity.</p> Signup and view all the answers

<p>When an acid is mixed with water, it releases $H_3O^+$ ions. When a base is mixed with water, it increases the concentration of $OH^⁻$ ions.</p> Signup and view all the answers

<p>Baking powder, when heated, produces carbon dioxide gas, which can turn limewater milky. Washing soda does not produce carbon dioxide upon heating.</p> Signup and view all the answers

<p>A neutralization reaction is when an acid and a base react to form salt and water. For example, $HCl(aq) + NaOH(aq) \rightarrow NaCl(aq) + H_2O(l)$.</p> Signup and view all the answers

<p>Baking soda is a mild base that neutralizes the excess hydrochloric acid produced in the stomach, providing relief from acidity.</p> Signup and view all the answers

<p>Turmeric in the curry acts as a natural indicator. Soap, being basic, changes the turmeric's color to reddish-brown. Rinsing with water removes the alkaline soap, and the turmeric reverts to its original yellow color.</p> Signup and view all the answers

<p>Adding water to a concentrated acid can cause the water to boil rapidly, splashing concentrated acid out of the container and potentially causing burns. This is due to the highly exothermic nature of the reaction, where heat is released very quickly. Adding acid to water allows the heat to be dissipated more safely.</p> Signup and view all the answers

<p>Metal oxides react with acids because they act as bases, neutralizing the acid to form a salt and water. This is a neutralization reaction. Metal oxides are classified as basic oxides because of their ability to neutralize acids.</p> Signup and view all the answers

<p>The solution with a pH of 3 is 1000 times more acidic than the solution with a pH of 6. This is because each unit change in pH represents a tenfold change in acidity, so a difference of 3 pH units (6-3) corresponds to $10^3$ or 1000 times more acidic.</p> Signup and view all the answers

<p>A strong acid completely ionizes in an aqueous solution, meaning it dissociates fully into its ions. An example is hydrochloric acid (HCl). A weak acid only partially ionizes, meaning only some of its molecules dissociate into ions. An example is acetic acid ($CH_3COOH$).</p> Signup and view all the answers

<p>An indicator signals the endpoint of a titration by changing color at or near the equivalence point, where the acid and base have completely neutralized each other. To be effective, an indicator must have a distinct color change within a narrow pH range that includes the equivalence point of the titration.</p> Signup and view all the answers

<p>A buffer solution resists changes in pH when small amounts of acid or base are added. Buffers are crucial in biological systems to maintain a stable pH for proper functioning of enzymes and other biochemical processes. An example is the carbonic acid-bicarbonate buffer system in blood, which maintains a stable pH by neutralizing excess acids or bases: $H_2CO_3(aq) \rightleftharpoons H^+(aq) + HCO_3^-(aq)$</p> Signup and view all the answers

<p>Neutralization is the reaction between an acid and a base, resulting in the formation of salt and water. Titration is a laboratory technique used to determine the concentration of an unknown acid or base by gradually adding a known concentration of a base or acid until neutralization occurs, which can be identified by an indicator or pH meter.</p> Signup and view all the answers

<p>In the given reaction, the conjugate acid-base pairs are: $NH_3$ (base) and $NH_4^+$ (conjugate acid), and $H_2O$ (acid) and $OH^-$ (conjugate base). Ammonia ($NH_3$) accepts a proton to form the ammonium ion ($NH_4^+$), while water ($H_2O$) donates a proton to form the hydroxide ion ($OH^-$).</p> Signup and view all the answers

<p>Pure water is neutral because the concentrations of $H^+$ and $OH^-$ ions are equal ($[H^+] = [OH^-]$). In acidic solutions, $[H^+] &gt; [OH^-]$, while in basic solutions, $[OH^-] &gt; [H^+]$.</p> Signup and view all the answers

<p>Acid rain forms when pollutants like sulfur dioxide ($SO_2$) and nitrogen oxides ($NO_x$) react with water, oxygen, and other chemicals in the atmosphere to form sulfuric and nitric acids. These acids fall to the earth as acid rain, which can acidify lakes and streams, damage forests, and corrode buildings and monuments.</p> Signup and view all the answers

<p>The compound must possess both a labile proton for Bronsted-Lowry acidity and a lone pair of electrons or pi system for Lewis basicity. Acidic activity is favored in high pH environments, basicity in low pH.</p> Signup and view all the answers

<p>Buffer capacity $\beta = 2.303 ([H_3O^+] + [OH^-] + \frac{K_a[HA]}{([H_3O^+] + K_a)})$. It describes the effectiveness of a buffer solution in resisting changes in pH upon addition of acid or base.</p> Signup and view all the answers

<p>Hammett parameters correlate substituent electronic effects with reaction rates/equilibria. $\Delta pK_a = \rho \sigma$, where $\rho$ is the reaction constant and $\sigma$ is the substituent constant. Limitations arise from steric hindrance and solvation effects.</p> Signup and view all the answers

<p>Use fluorescence spectrophotometry with a series of buffers covering the expected pH range for calibration. Plot fluorescence intensity vs. pH to obtain a calibration curve, correcting for inner-filter effects and photobleaching. Use the Stern-Volmer equation to account for quenching effects.</p> Signup and view all the answers

<p>The strength of $HA$ depends on the solvent's ability to stabilize ions. A less polar solvent reduces ionization, weakening $HA$. The titration curve will show a less pronounced endpoint and a smaller pH change near the equivalence point.</p> Signup and view all the answers

<p>First, titrate with a strong base to determine total acid concentration. Use a pH meter to determine the equivalence points for HCl and acetic acid. Use UV-Vis spectroscopy to quantify phenol concentration, using its molar absorptivity at a specific wavelength.</p> Signup and view all the answers

<p>Hammett acidity function ($H_0$) relies on indicator protonation, which is limited by indicator basicity and solvent effects. An alternative is computational methods using density functional theory (DFT) to calculate proton affinities, providing a more direct measure of acidity.</p> Signup and view all the answers

<p>Use a robust electrode material (e.g., glassy carbon) coated with a chemically inert polymer containing a redox-active quinone derivative. The quinone's redox potential is pH-dependent, measured by cyclic voltammetry. Stability requires chemical inertness and strong adhesion.</p> Signup and view all the answers

<p>Use temperature-programmed desorption of ammonia (TPD-NH3) to quantify total acidity. Use pyridine adsorption followed by infrared spectroscopy to distinguish between Bronsted and Lewis acid sites. XPS can provide information of the oxidation states to correlate with acidity.</p> Signup and view all the answers

<p>Concerted proton transfer involves simultaneous proton donation and acceptance, lowering the activation energy compared to stepwise transfer due to stabilization of the transition state. The potential energy diagram will show a single transition state for the concerted mechanism, as opposed to two for the stepwise mechanism. Tunneling may also be a factor.</p> Signup and view all the answers

<p>Purple</p> Signup and view all the answers

<p>Turmeric, red cabbage leaves, coloured petals of some flowers such as Hydrangea, Petunia and Geranium.</p> Signup and view all the answers

<p>Soap is basic in nature.</p> Signup and view all the answers

<p>Acids turn blue litmus paper red.</p> Signup and view all the answers

<p>Base</p> Signup and view all the answers

<p>Baking soda is a base and neutralizes excess acid in the stomach.</p> Signup and view all the answers

<p>Solution A</p> Signup and view all the answers

<p>Advantage: Natural indicators are readily available and environmentally friendly. Disadvantage: Natural indicators may not provide as sharp or distinct a color change as synthetic indicators, and might degrade more quickly.</p> Signup and view all the answers

<p>The solution is basic. Phenolphthalein is unsuitable because it changes color in the basic range (pH 8.3-10), making it difficult to accurately determine the equivalence point with a strong acid.</p> Signup and view all the answers

<p>The initial solution was likely a strong acid, contaminated with a trace amount of a volatile weak base like ammonia ($ ext{NH}_3$). The initial phenolphthalein test only detects the neutralization of the weak base due to it's high pH range, not the acidic solution. Methyl orange, with a much lower pH range, detects the strong base being added to the strong acid almost immediately.</p> Signup and view all the answers

Substances with a sour taste that turn blue litmus red.

Substances with a bitter taste that turn red litmus blue.

A method using litmus paper to identify acids and bases.

Substances like turmeric and red cabbage used to test pH.

Man-made substances like methyl orange used to identify acids/bases.

The reaction between an acid and a base to cancel each other's effects.

Turmeric turns yellow in acids and reddish-brown in bases.

A synthetic indicator that changes color at pH levels.

A synthetic indicator turning pink in basic solutions.

A purple dye from lichen used to test pH.

Baking soda neutralizes excess acidity to relieve heartburn.

Acids are known for their sour flavor.

Bases are recognized for their bitter taste.

Blue litmus turns red in acidic solutions.

Turmeric turns yellow in acidic solutions and reddish-brown in basic solutions.

Substances like red cabbage and flowers that show pH levels.

Man-made dyes like methyl orange and phenolphthalein that signal pH changes.

The process where an acid and a base interact and cancel each other's properties.

Litmus solution is made from a purple dye extracted from lichens.

Substances that signal whether a solution is acidic or basic.

Litmus solution is purple when neither acidic nor basic.

Acids and bases can neutralize flavors in cooking remedies.

Curry stains turn reddish-brown with soap, a base.

Some colored petals act as natural indicators for pH.

Litmus dye is extracted from lichens, a plant type.

Red cabbage leaves change color, indicating pH levels.

A common remedy for acidity that neutralizes stomach acid.

Turmeric shows yellow in acids and reddish-brown in bases.

Natural materials like turmeric and red cabbage indicate pH.

Substances that give food a sour taste.

Substances that impart a bitter taste.

Substances from nature that indicate acidity or basicity.

Man-made substances used to test for acids and bases.

Litmus solution is purple when neither acidic nor basic.

Curry stains turn reddish-brown with soap, which is basic.

The reaction where an acid cancels the effects of a base and vice versa.

Acids are known for their characteristic sour flavor in foods.

Bases have a characteristic bitter taste.

Blue litmus paper turns red in the presence of acids.

Red litmus paper turns blue in the presence of bases.

Natural indicators include turmeric and red cabbage.

Methyl orange is a synthetic indicator for pH.

Acids and bases neutralize each other's properties.

Turmeric turns yellow in acidic solutions and reddish-brown in basic ones.

Litmus solution appears purple when neutral.