Question

types of chemical reactions quiz chemistry b beach el(a - f) semester 2 3761 / module 7 chemical reactions 1. which of the following are examples of single replacement reactions? select all that apply \\(2k_{(s)} + 2hcl_{(aq)} \
ightarrow 2kcl (aq) + h_{2(g)}\\) \\(ca(oh)_{2(aq)} + 2hcl_{(aq)} \
ightarrow cacl_{2(aq)} + 2h_{2}o_{(l)}\\) \\(na_{2}s_{(aq)} + cd(no_{3})_{2(aq)} \
ightarrow cds_{(s)} + 2nano_{3(aq)}\\) \\(mg_{(s)} + zn(no_{3})_{2(aq)} \
ightarrow mg(no_{3})_{2(aq)} + zn_{(s)}\\)

Explanation:

A single - replacement reaction is of the form \(A + BC
ightarrow AC + B\), where a more reactive element replaces a less reactive element in a compound.

1. For the reaction \(2K_{(s)}+2HCl_{(aq)}

ightarrow2KCl_{(aq)}+H_2_{(g)}\):

• Here, potassium (\(K\)) is a metal and it replaces hydrogen (\(H\)) in hydrochloric acid (\(HCl\)). The general form \(A + BC

ightarrow AC + B\) is followed, with \(A = K\), \(B = H\), and \(C=Cl\). So this is a single - replacement reaction.

1. For the reaction \(Ca(OH)_{2(aq)}+2HCl_{(aq)}

ightarrow CaCl_{2(aq)}+2H_2O_{(l)}\):

• This is a neutralization reaction (a type of double - replacement reaction), where an acid (\(HCl\)) and a base (\(Ca(OH)_2\)) react to form a salt (\(CaCl_2\)) and water (\(H_2O\)). The general form of a double - replacement reaction is \(AB+CD

ightarrow AD + CB\), which is different from the single - replacement reaction form.

1. For the reaction \(Na_2S_{(aq)}+Cd(NO_3)_{2(aq)}

ightarrow CdS_{(s)}+2NaNO_3_{(aq)}\):

• This is a double - replacement reaction. The cations (\(Na^+\) and \(Cd^{2 +}\)) and anions (\(S^{2-}\) and \(NO_3^-\)) switch partners. The general form \(AB + CD

ightarrow AD+CB\) is followed, so it is not a single - replacement reaction.

1. For the reaction \(Mg_{(s)}+Zn(NO_3)_{2(aq)}

ightarrow Mg(NO_3)_{2(aq)}+Zn_{(s)}\):

• Magnesium (\(Mg\)) is a metal and it replaces zinc (\(Zn\)) in zinc nitrate (\(Zn(NO_3)_2\)). The general form \(A + BC

ightarrow AC + B\) is followed, with \(A = Mg\), \(B = Zn\), and \(C = NO_3^-\). So this is a single - replacement reaction.

Answer:

The reactions that are examples of single - replacement reactions are:

• \(2K_{(s)}+2HCl_{(aq)}

ightarrow2KCl_{(aq)}+H_2_{(g)}\)

• \(Mg_{(s)}+Zn(NO_3)_{2(aq)}

ightarrow Mg(NO_3)_{2(aq)}+Zn_{(s)}\)