$CATEGORY: Science - Khan Academy/2.Acids, Bases and Salts/2.Acids, Bases and Salts--Understanding of Chemical properties of acids and basis

//Multiple Choice

When magnesium reacts with hydrochloric acid, which gas is evolved?
{
~ Oxygen
~ Nitrogen
= Hydrogen
~ Carbon dioxide
}

What does magnesium chloride consist of?
{
= Mg⁺² and Cl⁻ ions
~ Mg⁺¹ and Cl⁻ ions
~ Mg⁻² and Cl⁺ ions
~ Mg⁺² and Cl⁺ ions
}

What is the reactivity series used for?
{
~ Determining the density of elements
= Listing elements in order of their reactivity
~ Identifying acids and bases
~ Balancing chemical equations
}

Zinc reacts with hydrochloric acid to form\:
{
~ Zinc hydroxide and oxygen gas
~ Zinc sulfate and hydrogen gas
= Zinc chloride and hydrogen gas
~ Zinc oxide and carbon dioxide
}

What test is used to confirm the presence of hydrogen gas?
{
~ Litmus test
= Pop sound test
~ Smell test
~ Flame test
}

What is the chemical formula of sodium zincate?
{
~ Na₂ZnO₃
= Na₂ZnO₂
~ NaZnO₂
~ Na₃ZnO₂
}

What happens to air inside the test tube during the pop sound test?
{
~ It cools rapidly
= It expands rapidly
~ It reacts with hydrogen gas
~ It becomes stationary
}

Which metal reacts with both acids and bases to release hydrogen gas?
{
~ Magnesium
= Zinc
~ Sodium
~ Copper
}

What is released during the reaction of metals with acids?
{
~ Oxygen gas
~ Carbon dioxide gas
= Hydrogen gas
~ Water vapor
}

Why doesn’t pure HCl act as an acid?
{
= It is covalent and doesn’t have ions
~ It is neutral
~ It only acts as an acid when heated
~ It doesn’t dissolve in water
}

What kind of reaction occurs when hydrogen reacts with oxygen?
{
~ Endothermic reaction
= Exothermic reaction
~ Neutral reaction
~ Decomposition reaction
}

What happens when nitric acid (HNO₃) reacts with metals?
{
~ It always releases hydrogen gas
~ It reacts with all metals
= It does not always release hydrogen gas
~ It does not react with any metal
}


//True or False

Metals reacting with acids produce hydrogen gas. {T}

Pure HCl consists of ions. {F}

Zinc reacts with sodium hydroxide to produce hydrogen gas. {T}

Zinc chloride is a base. {F}

Hydrogen is more reactive than magnesium. {F}

In general, metals react with bases to release hydrogen gas. {F}

Hydrogen gas burns with a pop sound. {T}

Magnesium chloride is electrically neutral. {T}

Bubbles in the reaction of zinc and HCl indicate hydrogen gas formation. {T}

The reactivity series is used to predict which metals displace hydrogen. {T}

Hydrogen gas is odorless and colorless. {T}

Sodium hydroxide reacts with all metals to release hydrogen gas. {F}

Combination reactions are generally exothermic. {T}

//Fill in the blanks

When magnesium reacts with hydrochloric acid, the products are ________.
{
~ MgO and H₂
= MgCl₂ and H₂
~ MgCl and O₂
~ Mg(OH)₂ and H₂O
}

Magnesium is ________ reactive than hydrogen in the reactivity series.
{
~ less
~ equally
= more
~ not
}

Zinc reacts with sodium hydroxide to produce ________.
{
= Sodium zincate and hydrogen gas
~ Sodium chloride and oxygen gas
~ Sodium hydroxide and hydrogen gas
~ Zinc oxide and sodium gas
}

The gas evolved during the reaction of metals with acids is ________.
{
~ Oxygen
~ Nitrogen
= Hydrogen
~ Carbon dioxide
}

Pure HCl has a ________ bond between hydrogen and chlorine.
{
~ Ionic
= Covalent
~ Metallic
~ Hydrogen
}

The reaction of hydrogen gas with oxygen gas forms ________.
{
~ HCl
~ CO₂
= Water
~ Salt
}

Magnesium chloride is a ________.
{
~ Metal
~ Gas
= Salt
~ Base
}

The reaction of acids with metals generally forms salt and ________.
{
~ Oxygen gas
= Hydrogen gas
~ Carbon dioxide
~ Heat
}

In the reaction of zinc with hydrochloric acid, the salt formed is ________.
{
~ Zinc sulfate
~ Zinc nitrate
= Zinc chloride
~ Sodium chloride
}

Hydrogen is ________ in the reactivity series than magnesium.
{
= Lower
~ Higher
~ Equal
~ Opposite
}

Bases generally ________ react with metals to form hydrogen gas.
{
= Do not
~ Always
~ Sometimes
~ Never
}

//Numericals



//Match the following

Match the following items from Column A with their correct corresponding options from Column B\:
{
=Hydrogen gas -> Produced in a pop sound test
=Magnesium chloride -> Formed when Mg reacts with HCl
=Sodium zincate -> Na₂ZnO₂
=Zinc chloride -> Salt formed when Zn reacts with HCl
=Reactivity series -> Lists elements by reactivity
=Pop sound test -> Identifies hydrogen gas
}


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