Class 10 : Practice Questions and Answers

In a double bond, one bond is a sigma bond and the other is a pi bond. The pi bond is formed by the sideways overlap of p-orbitals between the two carbon atoms.

Oxygen is essential for respiration. Cells use oxygen to break down glucose, releasing energy needed to function.

When an acid is added to water, it dissociates to release hydrogen ions (H+), making the solution acidic with a pH below 7.

Alkynes contain at least one triple bond between carbon atoms, making them unsaturated hydrocarbons with fewer hydrogen atoms than alkanes.

Lemon juice is acidic with a pH of approximately 3. Acids have a pH below 7, and lemon juice is naturally acidic due to the presence of citric acid.

In a displacement reaction, one element displaces another from a compound. In $A + BC \rightarrow AC + B$, element A displaces B from BC to form AC.

The IUPAC name for $CH_3\text{-}CH_2\text{-}CH=CH_2$ is 1-butene, as the double bond is between the first and second carbon atoms from the end closest to the double bond.

Non-metals typically form acidic oxides, not basic ones. For example, carbon dioxide is an acidic oxide, whereas metals like sodium form basic oxides.

Zinc is commonly used to coat metals like iron through galvanization, forming a protective layer that shields iron from rust and corrosion.

In $Cl_2$, chlorine has an oxidation state of 0. In $FeCl_3$, chlorine has an oxidation state of $-1$, while iron has $+3$. This highlights oxidation and reduction in the reaction.

Nylon is a synthetic polymer formed from carbon-based monomers. It is used in fabrics and various industrial applications due to its strength and flexibility.

In $CuSO_4 + Zn \rightarrow ZnSO_4 + Cu$, zinc is oxidized (loses electrons) and copper is reduced (gains electrons). This simultaneous oxidation and reduction makes it a redox reaction.

According to the Bronsted-Lowry theory, a base accepts a proton (H+) while an acid donates a proton. This expands the definition of acids and bases beyond the traditional Arrhenius concept.

A catalyst speeds up a chemical reaction by lowering the activation energy without being consumed in the process. Catalysts are vital in industrial processes such as the production of fertilizers.

Sodium reacts vigorously with water to produce hydrogen gas and sodium hydroxide, a characteristic reaction of alkali metals.

Sodium hydroxide (NaOH), also known as caustic soda, is commonly used in cleaning products due to its ability to break down grease and other contaminants.

A decomposition reaction involves the breakdown of a compound into two or more simpler substances, often requiring heat or light. An example is calcium carbonate breaking down into calcium oxide and carbon dioxide.

Diamond is an allotrope of carbon where carbon atoms are arranged in a crystal lattice, making it the hardest natural substance. Other allotropes include graphite and graphene.

When vinegar (acetic acid) reacts with baking soda (sodium bicarbonate), carbon dioxide gas is produced. This reaction is commonly used in science experiments and as a cleaning agent.

Carbon monoxide is a colorless, odorless, and poisonous gas formed during the incomplete combustion of carbon-containing materials. It can be deadly when inhaled in large amounts.