Chemical Reactions of Metals with Acids

Hydrogen gas

Salt

Salt + Hydrogen gas

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

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

<p>Sodium zincate and hydrogen gas</p> Signup and view all the answers

<p>No</p> Signup and view all the answers

<p>Metal carbonates and metal hydrogencarbonates</p> Signup and view all the answers

<p>$Na_2CO_3$</p> Signup and view all the answers

<p>Calcium hydroxide solution</p> Signup and view all the answers

<p>$2HCl(aq) + Mg(s) \rightarrow MgCl_2(aq) + H_2(g)$</p> Signup and view all the answers

<p>Acid + Metal → Salt + Hydrogen gas</p> Signup and view all the answers

<p>$2NaOH(aq) + Zn(s) \rightarrow Na_2ZnO_2(aq) + H_2(g)$</p> Signup and view all the answers

<p>The lime water turns milky, which indicates the presence of carbon dioxide.</p> Signup and view all the answers

<p>$Na_2CO_3(s) + 2HCl(aq) \rightarrow 2NaCl(aq) + H_2O(l) + CO_2(g)$</p> Signup and view all the answers

<p>$NaHCO_3(s) + HCl(aq) \rightarrow NaCl(aq) + H_2O(l) + CO_2(g)$</p> Signup and view all the answers

<p>The reactivity of metals varies, and only certain metals are reactive enough to displace hydrogen from sodium hydroxide.</p> Signup and view all the answers

<p>$Na_2ZnO_2$, It is produced in the reaction between zinc and sodium hydroxide.</p> Signup and view all the answers

<p>Carbon dioxide ($CO_2$).</p> Signup and view all the answers

<p>$ZnSO_4$</p> Signup and view all the answers

<p>The ability of a metal to react with sodium hydroxide depends on its electrochemical potential and the stability of the resulting metal complex (e.g., sodium zincate). Metals with sufficiently negative reduction potentials can displace hydrogen from the hydroxide, but others may form insoluble oxides or hydroxides instead.</p> Signup and view all the answers

<p>When carbon dioxide gas (produced from the reaction) is passed through lime water (calcium hydroxide solution), it reacts to form calcium carbonate, an insoluble precipitate, and water. The lime water turns milky.</p> Signup and view all the answers

<p>The reaction can be performed in a closed system connected to a gas burette. By measuring the displacement of water in the burette, the volume of the gas produced can be determined at room temperature and pressure and then converted to STP conditions using the ideal gas law ($PV = nRT$).</p> Signup and view all the answers

<p>$Na_2CO_3 + 2HCl \rightarrow 2NaCl + H_2O + CO_2$; $NaHCO_3 + HCl \rightarrow NaCl + H_2O + CO_2$. Sodium carbonate requires twice the amount of hydrochloric acid to fully react compared to sodium hydrogencarbonate.</p> Signup and view all the answers

<p>Use a water displacement setup: React the metal and acid in a closed flask connected to a graduated cylinder inverted in a water-filled trough. The hydrogen gas displaces the water in the cylinder, allowing for volume measurement.</p> Signup and view all the answers

<p>In the reaction between a metal and an acid, the metal undergoes oxidation (loses electrons), and hydrogen ions from the acid undergo reduction (gain electrons) to form hydrogen gas. These simultaneous oxidation and reduction processes define a redox reaction.</p> Signup and view all the answers

<p>Passivation can prevent the reaction. Some metals, like aluminum, form a protective oxide layer on their surface that prevents the acid from reacting with the underlying metal, even though aluminum is high in the activity series.</p> Signup and view all the answers

<p>At STP, 1 mole of gas occupies 22.4 L. So, 5 L of $CO_2$ is approximately 0.223 moles. From the reaction $Na_2CO_3 + 2HCl \rightarrow 2NaCl + H_2O + CO_2$, 1 mole of $Na_2CO_3$ produces 1 mole of $CO_2$. Therefore, 0.223 moles of $Na_2CO_3$ are required. The molar mass of $Na_2CO_3$ is approximately 106 g/mol, so the mass required is about 23.6 g.</p> Signup and view all the answers

<p>Increasing the concentration of the acid generally increases the rate of hydrogen gas production. This is because a higher concentration of acid provides more hydrogen ions ($H^+$) per unit volume, leading to more frequent collisions and a faster reaction rate.</p> Signup and view all the answers

<p>Indicators are used to visually signal the endpoint of the reaction, which should be close to the equivalence point. Methyl orange or methyl red would be suitable indicators as they change color in the acidic pH range resulting from the formation of carbonic acid during the titration.</p> Signup and view all the answers

<p>$2X(s) + 6HClO_4(aq) \rightarrow 2X(ClO_4)_3(aq) + 3H_2(g)$. The hydrogen gas ($H_2$) evolved could potentially react explosively with a strong oxidizing agent like fluorine ($F_2$) or oxygen ($O_2$) under appropriate conditions, forming $HF$ or $H_2O$ respectively.</p> Signup and view all the answers

<p>The reaction of $Na_2CO_3$ with a weak acid generates $HCO_3^-$ and $Na^+$. The $HCO_3^-$ then reacts further to produce $H_2CO_3$ which decomposes into $CO_2$ and $H_2O$. This process is relatively slow and subject to equilibria. With $NaHCO_3$, the reaction proceeds more directly, without a prior buffering action, leading to faster $CO_2$ evolution. $Na_2CO_3 + HA \rightleftharpoons NaHCO_3 + NaA$, followed by $NaHCO_3 + HA \rightleftharpoons H_2CO_3 + NaA$ and $H_2CO_3 \rightleftharpoons H_2O + CO_2$. For $NaHCO_3$: $NaHCO_3 + HA \rightarrow H_2CO_3 + NaA$ which decomposes into $H_2O + CO_2$ more promptly.</p> Signup and view all the answers

<p>A mixed metalate salt containing both sodium and potassium could form. A plausible formula is $NaKZnO_2(aq)$. This assumes zinc maintains a coordination number of 4 in the alkaline solution, forming a tetrahedral zincate complex.</p> Signup and view all the answers

<p>To facilitate the reaction despite the unfavorable reduction potential, one could employ electrochemistry by applying an external potential to force oxidation of the metal. Alternatively, complexing agents that selectively bind $M^{2+}$ could lower its effective concentration, shifting the equilibrium favorably. Finally, an electrochemical cell could be setup using an inert electrode and applying sufficient overpotential.</p> Signup and view all the answers

<p>Due to the larger ionic radius and lower hydration energy of $Rb^+$ compared to $Na^+$, $Rb_2CO_3$ might exhibit a slightly higher solubility and potentially a marginally faster reaction rate with dilute HCl. The properties of the evolved $CO_2$ gas will remain the same, as it's independent of the cation.</p> Signup and view all the answers

<p>Zinc will react preferentially with sulfuric acid due to its more negative standard reduction potential compared to iron. This will be further enhanced by a galvanic effect where zinc acts as the anode and iron as the cathode, accelerating zinc dissolution. The reaction will proceed until the zinc is fully consumed, after which iron will start to react.</p> Signup and view all the answers

<p>The bulky tetraalkylammonium cation could sterically hinder the approach of hydroxide ions to the zinc surface, potentially slowing the reaction rate. However, the weaker ion pairing between the large cation and the zincate anion might enhance the solubility of the zincate complex in solution, potentially influencing the overall equilibrium.</p> Signup and view all the answers

<p>One approach is to use an aqueous solution of monoethanolamine (MEA) to selectively absorb $CO_2$. The $CO_2$ reacts with MEA to form a carbamate. $CO_2(g) + 2RNH_2(aq) \rightleftharpoons RNHCOO^-(aq) + RNH_3^+(aq)$. The $H_2$ remains unreacted and can be separated. The $CO_2$ can be released by heating the solution, reversing the reaction. A metal-amine complex could also be engineered to bind $CO_2$ reversibly.</p> Signup and view all the answers

<p>By varying the flow rates and thus the residence time of the reactants in the microfluidic channel, one can obtain kinetic data. Inline spectroscopic detection of $CO_2$ allows for real-time monitoring of product formation. Analyzing the $CO_2$ production profiles as a function of residence time for both $Na_2CO_3$ and $NaHCO_3$ reactions enables determination of the rate constants and differentiation of reaction mechanisms, e.g., by fitting the data to appropriate kinetic models.</p> Signup and view all the answers

<p>In aqua regia ($HNO_3$ and $HCl$), the reaction with zinc can produce not only zinc chloride ($ZnCl_2$) but also nitrogen oxides like $NO$ or $NO_2$, and potentially ammonium ions ($NH_4^+$). At higher nitric acid concentrations and lower temperatures, $NO_x$ formation is favored: $Zn + 2HNO_3 + 2HCl \rightarrow ZnCl_2 + 2NO_2 + 2H_2O$ (simplified). At lower nitric acid concentrations and elevated temperatures, reduction to $NH_4^+$ becomes more likely: $4Zn + HNO_3 + 10HCl \rightarrow 4ZnCl_2 + NH_4Cl + 3H_2O$.</p> Signup and view all the answers

<p>Hydrogen gas</p> Signup and view all the answers

<p>$2NaOH(aq) + Zn(s) \rightarrow Na_2ZnO_2(s) + H_2(g)$</p> Signup and view all the answers

<p>No</p> Signup and view all the answers

<p>$Na_2CO_3$</p> Signup and view all the answers

<p>$NaHCO_3$</p> Signup and view all the answers

<p>Carbon dioxide</p> Signup and view all the answers

<p>$Ca(OH)_2$</p> Signup and view all the answers

<p>The lime water turns milky due to the formation of calcium carbonate.</p> Signup and view all the answers

<p>In the reaction between a metal and an acid, the metal displaces hydrogen ions from the acid, forming a salt and releasing hydrogen gas. The metal takes the place of the hydrogen.</p> Signup and view all the answers

<p>The reaction would still produce carbon dioxide gas, but it would likely be slower and less vigorous than with $HCl$. Ethanoic acid is a weak acid, meaning it does not fully dissociate in water, resulting in a lower concentration of $H^+$ ions available to react with the carbonate or hydrogencarbonate. This lower $H^+$ concentration reduces the reaction rate.</p> Signup and view all the answers

A reaction where a metal displaces hydrogen from acids, forming salt and hydrogen gas.

The general formula representing the reaction of an acid with a metal.

The reaction between zinc and sodium hydroxide produces sodium zincate and hydrogen gas.

A chemical compound (Na2CO3) that reacts with acids to produce carbon dioxide and salt.

A compound (NaHCO3) that reacts with acids to form carbon dioxide, water, and salt.

A strong acid often used in reactions with carbonates and bicarbonates.

The gas produced from the reaction of carbonates with acids, which can be tested using lime water.

The solid product formed from the reaction of zinc and sodium hydroxide.

A test using calcium hydroxide solution to detect carbon dioxide by observing cloudiness.

Reactions involving an acid and a base that produce salt and water, often with gas release.

Some metals can react with acids to displace hydrogen and form salts.

Zinc reacts with hydrochloric acid to produce zinc chloride and hydrogen gas.

Sodium carbonate reacts with hydrochloric acid to produce sodium chloride, water, and carbon dioxide.

Sodium hydrogencarbonate reacts with hydrochloric acid to form sodium chloride, water, and carbon dioxide.

Hydrogen gas is a common product in metal-acid reactions.

A solution used to test for carbon dioxide by forming calcium carbonate.

Metal carbonates react with acids to liberate carbon dioxide gas.

Metal hydrogencarbonates react with acids, producing carbon dioxide and salt.

When zinc is added to sodium hydroxide, it produces sodium zincate and hydrogen gas.

In displacement reactions, a more reactive metal can displace a less reactive metal from its compound.

Reacts to produce carbon dioxide, salt, and water.

Both sodium carbonate and sodium hydrogencarbonate produce carbon dioxide with HCl.

Sodium carbonate (Na2CO3) generates sodium chloride, water, and carbon dioxide with HCl.

Sodium hydrogencarbonate (NaHCO3) reacts with HCl forming water, salt, and carbon dioxide.

The products include carbon dioxide, salt, and water.

Used to observe reactions with metal carbonates and bicarbonates.

Used to confirm the presence of carbon dioxide by forming a cloudy solution.

Metal carbonate + acid → salt + water + carbon dioxide.

Na2CO3 + 2HCl → 2NaCl + H2O + CO2.

NaHCO3 + HCl → NaCl + H2O + CO2.

The process where a metal replaces hydrogen in acids, forming salt and hydrogen gas.

The product formed when zinc reacts with sodium hydroxide, represented as Na2ZnO2.

Sodium carbonate reacts with hydrochloric acid to produce sodium chloride, water, and carbon dioxide.

Sodium hydrogencarbonate reacts with hydrochloric acid to yield sodium chloride, water, and carbon dioxide.

Both sodium carbonate and sodium hydrogencarbonate produce carbon dioxide when reacted with HCl.

Carbon dioxide in water forms carbonic acid, contributing to the fizzing observed.

Lime water turns cloudy when carbon dioxide is bubbled through it, confirming CO2 presence.

Testing with acids in separate tubes to observe distinct reactions with carbonates and bicarbonates.

Acid + Metal carbonate → Salt + Water + Carbon dioxide.

Hydrogen gas is produced when metals react with acids or bases, a key indicator of the reaction.

Zinc displaces hydrogen in acid to form salt and hydrogen gas.

Sodium carbonate reacts with acid to produce carbon dioxide, water, and salt.

Sodium hydrogencarbonate reacts with acid to form carbon dioxide, water, and salt.

Hydrogen gas is formed as a product in metal-acid reactions.

Na2CO3 + 2HCl → 2NaCl + H2O + CO₂ is the reaction of sodium carbonate with hydrochloric acid.

NaHCO3 + HCl → NaCl + H2O + CO₂ is the reaction of sodium hydrogencarbonate with hydrochloric acid.

2NaOH + Zn → Na2ZnO2 + H2 describes the reaction of zinc with sodium hydroxide.

Both sodium carbonate and sodium hydrogencarbonate produce gas when reacting with HCl.