Question

Which of the following has more moles of H+ ions?
10mL of 0.1M H2SO4
20mL of 0.05M H2SO4
10mL of 0.1 M HCI
25mL of 0.05M H2SO4

Answer 1

Given that,

Volume of $H_{2}SO_{4}$ = 10 mL and molarity is 0.1M

Volume of $H_{2}SO_{4}$ = 20 mL and molarity is 0.05M

Volume of $HCl$ = 10 mL and molarity is 0.1M

Volume of $H_{2}SO_{4}$ = 25 mL and molarity is 0.05M

(I). 10 mL of 0.1M $H_{2}SO_{4}$

We need to find the moles of  $H_{2}SO_{4}$

Using formula of moles

$\text{Moles}=\text{molarity} \times volume\ of\ solution}$

Put the value into the formula

$\text{Moles}=0.1\times10\times10^{-3}$

$\text{Moles}=0.001$

We know that,

$H_{2}SO_{4}$ dissolves in $H^{+}_{2}$ and $SO^{-2}_{4}.$

We need to find the mole of H⁺ in $H_{2}SO_{4}$

Using formula for moles

$0.001\ moles\ of\ 2H^{+}$

Moles in H⁺ is

$M=2\times0.001$

$M=0.002$

(II). 20 mL of 0.05M $H_{2}SO_{4}$

We need to find the moles of  $H_{2}SO_{4}$

Using formula of moles

$\text{Moles}=\text{molarity}\times volume\ of\ solution}$

Put the value into the formula

$\text{Moles}=0.05\times20\times10^{-3}$

$\text{Moles}=0.001$

We know that,

$H_{2}SO_{4}$ dissolves in $H^{+}_{2}$ and $SO^{-2}_{4}.$

We need to find the mole of H⁺ in $H_{2}SO_{4}$

Using formula for moles

$0.001\ moles\ of\ 2H^{+}$

Moles in H⁺ is

$M=2\times0.001$

$M=0.002$

(III). 10 mL of 0.1M HCl

We need to find the moles of Hcl

Using formula of moles

$\text{Moles}=\text{molarity}\times volume\ of\ solution}$

Put the value into the formula

$\text{Moles}=0.1\times10\times10^{-3}$

$\text{Moles}=0.001$

One H⁺ is in HCl.

So, the moles of  H⁺ in HCl is 0.001.

(IV). 25 mL of 0.05M $H_{2}SO_{4}$

We need to find the moles of  $H_{2}SO_{4}$

Using formula of moles

$\text{Moles}=\text{molarity}\times volume\ of\ solution}$

Put the value into the formula

$\text{Moles}=0.05\times25\times10^{-3}$

$\text{Moles}=0.0013$

We know that,

$H_{2}SO_{4}$ dissolves in $H^{+}_{2}$ and $SO^{-2}_{4}.$

We need to find the mole of H⁺ in $H_{2}SO_{4}$

Using formula for moles

$0.0013\ moles\ of\ 2H^{+}$

Moles in H⁺ is

$M=2\times0.0013$

$M=0.0026$

Hence, The more moles of H⁺ in $H_{2}SO_{4}$ is 0.0026.

(IV) is correct option.