Chapter 20, Problem 90CWP

 (a)

Interpretation Introduction

Interpretation: The authenticity of the given statement is to be determined.

Concept introduction: The alkali metals occur in the combined state and occur in the minerals in the earth’s crust.

The melting point of gallium is $29.76{}^{\circ }\text{C}$, that is very close to the room temperature.

Reaction of calcium with water is,

$\text{Ca}\left(s\right)+2{\text{H}}_{\text{2}}\text{O}\left(l\right)\stackrel{}{\to }\text{Ca}{\left(\text{OH}\right)}_2\left(aq\right)+{\text{H}}_{\text{2}}\left(g\right)$

Reaction of aluminum trichloride with water is,

${\text{AlCl}}_3\left(s\right)+3{\text{H}}_{\text{2}}\text{O}\left(l\right)\stackrel{}{\to }\text{Al}{\left(\text{OH}\right)}_3\left(aq\right)+\text{HCl}\left(aq\right)$

Lithium reacts in the presence of oxygen as,

$\text{4Li}\left(s\right)+{\text{O}}_{\text{2}}\left(g\right)\underset{}{\to }2{\text{Li}}_{\text{2}}\text{O}\left(s\right)$

To determine: The authenticity of the statement, “The alkali metals are found in the earth’s crust in the form of pure elements.”

(b)

Interpretation Introduction

Interpretation: The authenticity of the given statement is to be determined.

Concept introduction: The alkali metals occur in the combined state and occur in the minerals in the earth’s crust.

The melting point of gallium is $29.76{}^{\circ }\text{C}$, that is very close to the room temperature.

Reaction of calcium with water is,

$\text{Ca}\left(s\right)+2{\text{H}}_{\text{2}}\text{O}\left(l\right)\stackrel{}{\to }\text{Ca}{\left(\text{OH}\right)}_2\left(aq\right)+{\text{H}}_{\text{2}}\left(g\right)$

Reaction of aluminum trichloride with water is,

${\text{AlCl}}_3\left(s\right)+3{\text{H}}_{\text{2}}\text{O}\left(l\right)\stackrel{}{\to }\text{Al}{\left(\text{OH}\right)}_3\left(aq\right)+\text{HCl}\left(aq\right)$

Lithium reacts in the presence of oxygen as,

$\text{4Li}\left(s\right)+{\text{O}}_{\text{2}}\left(g\right)\underset{}{\to }2{\text{Li}}_{\text{2}}\text{O}\left(s\right)$

To determine: The authenticity of the statement, “Gallium has one of the highest melting points known for metals.”

(c)

Interpretation Introduction

Interpretation: The authenticity of the given statement is to be determined.

Concept introduction: The alkali metals occur in the combined state and occur in the minerals in the earth’s crust.

The melting point of gallium is $29.76{}^{\circ }\text{C}$, that is very close to the room temperature.

Reaction of calcium with water is,

$\text{Ca}\left(s\right)+2{\text{H}}_{\text{2}}\text{O}\left(l\right)\stackrel{}{\to }\text{Ca}{\left(\text{OH}\right)}_2\left(aq\right)+{\text{H}}_{\text{2}}\left(g\right)$

Reaction of aluminum trichloride with water is,

${\text{AlCl}}_3\left(s\right)+3{\text{H}}_{\text{2}}\text{O}\left(l\right)\stackrel{}{\to }\text{Al}{\left(\text{OH}\right)}_3\left(aq\right)+\text{HCl}\left(aq\right)$

Lithium reacts in the presence of oxygen as,

$\text{4Li}\left(s\right)+{\text{O}}_{\text{2}}\left(g\right)\underset{}{\to }2{\text{Li}}_{\text{2}}\text{O}\left(s\right)$

To determine: The authenticity of the statement, “When calcium reacts with water, one of the product is ${\text{H}}_{\text{2}}\left(g\right)$.”

(d)

Interpretation Introduction

Interpretation: The authenticity of the given statement is to be determined.

Concept introduction: The alkali metals occur in the combined state and occur in the minerals in the earth’s crust.

The melting point of gallium is $29.76{}^{\circ }\text{C}$, that is very close to the room temperature.

Reaction of calcium with water is,

$\text{Ca}\left(s\right)+2{\text{H}}_{\text{2}}\text{O}\left(l\right)\stackrel{}{\to }\text{Ca}{\left(\text{OH}\right)}_2\left(aq\right)+{\text{H}}_{\text{2}}\left(g\right)$

Reaction of aluminum trichloride with water is,

${\text{AlCl}}_3\left(s\right)+3{\text{H}}_{\text{2}}\text{O}\left(l\right)\stackrel{}{\to }\text{Al}{\left(\text{OH}\right)}_3\left(aq\right)+\text{HCl}\left(aq\right)$

Lithium reacts in the presence of oxygen as,

$\text{4Li}\left(s\right)+{\text{O}}_{\text{2}}\left(g\right)\underset{}{\to }2{\text{Li}}_{\text{2}}\text{O}\left(s\right)$

To determine: The authenticity of the statement, “When ${\text{AlCl}}_{\text{3}}$ reacts with water, it produces an acidic solution.”

(e)

Interpretation Introduction

Interpretation: The authenticity of the given statement is to be determined.

Concept introduction: The alkali metals occur in the combined state and occur in the minerals in the earth’s crust.

The melting point of gallium is $29.76{}^{\circ }\text{C}$, that is very close to the room temperature.

Reaction of calcium with water is,

$\text{Ca}\left(s\right)+2{\text{H}}_{\text{2}}\text{O}\left(l\right)\stackrel{}{\to }\text{Ca}{\left(\text{OH}\right)}_2\left(aq\right)+{\text{H}}_{\text{2}}\left(g\right)$

Reaction of aluminum trichloride with water is,

${\text{AlCl}}_3\left(s\right)+3{\text{H}}_{\text{2}}\text{O}\left(l\right)\stackrel{}{\to }\text{Al}{\left(\text{OH}\right)}_3\left(aq\right)+\text{HCl}\left(aq\right)$

Lithium reacts in the presence of oxygen as,

$\text{4Li}\left(s\right)+{\text{O}}_{\text{2}}\left(g\right)\underset{}{\to }2{\text{Li}}_{\text{2}}\text{O}\left(s\right)$

To determine: The authenticity of the statement, “Lithium reacts in the presence of excess oxygen gas to form lithium peroxide.”