Question

1.Which one of the following species cannot act as a base?

Select one:

a. H₂O

b. Cl^–

c. NH₄⁺

d. OH^–

e. NH₃

_2.

A gas with an empirical formula NO₂ is weighed in a 1 L flask and found to have a mass of 4.0 g. What is its molecular formula? (1 mol of an ideal gas occupies 23.0 L under the conditions of this experiment).

Select one:

a. N₂O₄

b. N₄O₈

c. NO

d. NO₂

e. N₂O

3.

When calcium hydroxide is reacted with excess nitric acid, it produces:

Select one:

a. a solution of Ca²⁺(aq) and OH^–(aq) ions

b. calcium nitrate solution

c. carbon dioxide gas

d. a basic solution

e. hydrogen gas

4.

A dilute aqueous acid was reacted with a white solid to produce a gas. This gas makes limewater turn cloudy and white. Which of the following could be the identity of the white solid?

Select one:

a. NaOH

b. NaHSO₃

c. NaCl

d. NaNO₃

e. NaHCO₃

_5.

When magnesium is reacted with hydrochloric acid, it produces:

Select one:

a. a spark

b. a basic solution

c. carbon dioxide gas

d. a solution containing Mg²⁺ (aq) and Cl^– (aq) ions

e. chlorine gas

Answer 1

1 ) answer : c. NH₄⁺

explanation: NH4+ is the acid that cannot act as a base because it came form base NH3

2)   answer : a ) N2O4

moles of NO2 = 4 / (14+ 32) = 4 / 46

1 mol gas can occupy ------------------>23 L

4/46 mol gas can occupy ---------------> 23 x 4 / 46 = 2 = n

molecular formula = n x NO2 = 2 x NO2 = N2O4

3) answer : b. calcium nitrate solution

Ca(OH)2 + 2HNO3 ---------------> Ca(NO3)2 + 2H2O

                                                    (calcium nitrate)

4) answer :e. NaHCO₃

NaHCO3 + HCl ---------------------> NaCl + H2O + CO2

CO2 gas released which turns lime water milky

Ca(OH)2 + CO2 ------------------> CaCO3 (s) + H2O

5) answer: d. a solution containing Mg²⁺ (aq) and Cl^– (aq) ions

Mg + 2HCl --------------------> MgCl2 + H2

MgCl2 -----------------> Mg+2 + 2Cl-