Chapter 21, Problem 21.11P

(a)

Interpretation Introduction

Interpretation:

The species that is being oxidized in the given balanced redox reaction has to be identified.

$2Cr{O}_2^{-}\left(aq\right)+2H_{2}O\left(l\right)+6Cl{O}^{-}\left(aq\right)\to 2Cr{O}_4^{2-}\left(aq\right)+3C{l}_2\left(g\right)+4O{H}^{-}\left(aq\right)$

Concept Introduction:

An electrochemical cell is a device in which a redox reaction is used to convert chemical energy into electrical energy. Such device is also known as the galvanic or voltaic cell.

Galvanic cell consists of two half-cells. The redox reaction occurs in these half-cells. The half-cell in which the reduction reaction occurs is known as the reduction half-cell, whereas the half-cell in which the oxidation reaction occurs is known as the oxidation half-cell.

Anode: The electrode where the oxidation occurs is called as an anode. It is a negatively charged electrode.

Cathode: The electrode where reduction occurs is called as a cathode. It is a positively charged electrode.

Oxidation: The gain of oxygen or the loss of hydrogen or the loss of an electron in a species during a redox reaction is called as oxidation.

Reduction: The loss of oxygen or the gain of hydrogen or the gain of an electron in a species during a redox reaction is called as reduction.

(b)

Interpretation Introduction

Interpretation:

The species that is being reduced in the given redox reaction has to be identified.

$2Cr{O}_2^{-}\left(aq\right)+2H_{2}O\left(l\right)+6Cl{O}^{-}\left(aq\right)\to 2Cr{O}_4^{2-}\left(aq\right)+3C{l}_2\left(g\right)+4O{H}^{-}\left(aq\right)$

Concept Introduction:

An electrochemical cell is a device in which a redox reaction is used to convert chemical energy into electrical energy. Such device is also known as the galvanic or voltaic cell.

Galvanic cell consists of two half-cells. The redox reaction occurs in these half-cells. The half-cell in which the reduction reaction occurs is known as the reduction half-cell, whereas the half-cell in which the oxidation reaction occurs is known as the oxidation half-cell.

Anode: The electrode where the oxidation occurs is called as an anode. It is a negatively charged electrode.

Cathode: The electrode where reduction occurs is called as a cathode. It is a positively charged electrode.

Oxidation: The gain of oxygen or the loss of hydrogen or the loss of an electron in a species during a redox reaction is called as oxidation.

Reduction: The loss of oxygen or the gain of hydrogen or the gain of an electron in a species during a redox reaction is called as reduction.

(c)

Interpretation Introduction

Interpretation:

The oxidizing agent in the given redox reaction has to be identified.

$2Cr{O}_2^{-}\left(aq\right)+2H_{2}O\left(l\right)+6Cl{O}^{-}\left(aq\right)\to 2Cr{O}_4^{2-}\left(aq\right)+3C{l}_2\left(g\right)+4O{H}^{-}\left(aq\right)$

Concept Introduction:

An electrochemical cell is a device in which a redox reaction is used to convert chemical energy into electrical energy. Such device is also known as the galvanic or voltaic cell.

Galvanic cell consists of two half-cells. The redox reaction occurs in these half-cells. The half-cell in which the reduction reaction occurs is known as the reduction half-cell, whereas the half-cell in which the oxidation reaction occurs is known as the oxidation half-cell.

Anode: The electrode where the oxidation occurs is called as an anode. It is a negatively charged electrode.

Cathode: The electrode where reduction occurs is called as a cathode. It is a positively charged electrode.

Oxidation: The gain of oxygen or the loss of hydrogen or the loss of an electron in a species during a redox reaction is called as oxidation.

Reduction: The loss of oxygen or the gain of hydrogen or the gain of an electron in a species during a redox reaction is called as reduction.

Reducing agent: The substance that reduces other species and gets oxidized is called as a reducing agent.

Oxidizing agent: The substance that oxidizes other species and gets reduced is called as an oxidizing agent.

(d)

Interpretation Introduction

Interpretation:

The reducing agent in the given redox reaction has to be identified.

$2Cr{O}_2^{-}\left(aq\right)+2H_{2}O\left(l\right)+6Cl{O}^{-}\left(aq\right)\to 2Cr{O}_4^{2-}\left(aq\right)+3C{l}_2\left(g\right)+4O{H}^{-}\left(aq\right)$

Concept Introduction:

An electrochemical cell is a device in which a redox reaction is used to convert chemical energy into electrical energy. Such device is also known as the galvanic or voltaic cell.

Galvanic cell consists of two half-cells. The redox reaction occurs in these half-cells. The half-cell in which the reduction reaction occurs is known as the reduction half-cell, whereas the half-cell in which the oxidation reaction occurs is known as the oxidation half-cell.

Anode: The electrode where the oxidation occurs is called as an anode. It is a negatively charged electrode.

Cathode: The electrode where reduction occurs is called as a cathode. It is a positively charged electrode.

Oxidation: The gain of oxygen or the loss of hydrogen or the loss of an electron in a species during a redox reaction is called as oxidation.

Reduction: The loss of oxygen or the gain of hydrogen or the gain of an electron in a species during a redox reaction is called as reduction.

Reducing agent: The substance that reduces other species and gets oxidized is called as a reducing agent.

Oxidizing agent: The substance that oxidizes other species and gets reduced is called as an oxidizing agent.

(e)

Interpretation Introduction

Interpretation:

Between which species the electron transfers occur has to be determined.

$2Cr{O}_2^{-}\left(aq\right)+2H_{2}O\left(l\right)+6Cl{O}^{-}\left(aq\right)\to 2Cr{O}_4^{2-}\left(aq\right)+3C{l}_2\left(g\right)+4O{H}^{-}\left(aq\right)$

Concept Introduction:

An electrochemical cell is a device in which a redox reaction is used to convert chemical energy into electrical energy. Such device is also known as the galvanic or voltaic cell.

Galvanic cell consists of two half-cells. The redox reaction occurs in these half-cells. The half-cell in which the reduction reaction occurs is known as the reduction half-cell, whereas the half-cell in which the oxidation reaction occurs is known as the oxidation half-cell.

The electrons flow from anode to cathode through the external wire of the circuit. A salt bridge is used to complete the cell circuit.

Salt bridge: It is a U-shaped tube filled with concentrated solution of inert electrolytes such as $\text{KCl,}{\text{KNO}}_{\text{3}}\text{and so on}\text{.}$. The ions that are present in the tube do not take part in the reaction.

Anode: The electrode where the oxidation occurs is called as an anode. It is a negatively charged electrode.

Cathode: The electrode where reduction occurs is called as a cathode. It is a positively charged electrode.

(f)

Interpretation Introduction

Interpretation:

The balanced molecular equation with given spectator ion ${\text{Na}}^{\text{+}}$ has to be determined.

$2Cr{O}_2^{-}\left(aq\right)+2H_{2}O\left(l\right)+6Cl{O}^{-}\left(aq\right)\to 2Cr{O}_4^{2-}\left(aq\right)+3C{l}_2\left(g\right)+4O{H}^{-}\left(aq\right)$

Concept Introduction:

An electrochemical cell is a device in which a redox reaction is used to convert chemical energy into electrical energy. Such device is also known as the galvanic or voltaic cell.

Galvanic cell consists of two half-cells. The redox reaction occurs in these half-cells. The half-cell in which the reduction reaction occurs is known as the reduction half-cell, whereas the half-cell in which the oxidation reaction occurs is known as the oxidation half-cell.

The electrons flow from anode to cathode through the external wire of the circuit. A salt bridge is used to complete the cell circuit.

Salt bridge: It is a U-shaped tube filled with concentrated solution of inert electrolytes such as $\text{KCl,}{\text{KNO}}_{\text{3}}\text{and so on}\text{.}$. The ions that are present in the tube do not take part in the reaction.

Anode: The electrode where the oxidation occurs is called as an anode. It is a negatively charged electrode.

Cathode: The electrode where reduction occurs is called as a cathode. It is a positively charged electrode.