Halogens and Acids-Bases Lecture Notes

Flashcards covering halogen chemical properties, physical trends in Group 17, and fundamental Acid-Base theories (Arrhenius and Brønsted-Lowry).

What are the chemical products when chlorine ($Cl_{2}$) reacts with water ($H_{2}O$)?

$HCl + HOCl$ (acid hypochlorous)

What are the chemical products when bromine ($Br_{2}$) reacts with water ($H_{2}O$)?

$HBr + HOBr$ (acid hypobromus)

What are the chemical products when iodine ($I_{2}$) reacts with water ($H_{2}O$)?

$HI + HOI$ (acid hypoiodus)

What is the chemical equation for the reaction between chlorine ($Cl_{2}$) and sodium hydroxide ($NaOH$)?

$$Cl_{2} + 2NaOH \rightarrow NaCl + NaOCl + H_{2}O$$

What is the name of the chemical compound $NaOBr$?

Sodium hypobromide

What is the product of the reaction between $3Cl_{2}$ and $2Fe$?

$2FeCl_{3}$ (Iron (III) chloride)

What are the colors and states of fluorine ($F_{2}$) and chlorine ($Cl_{2}$)?

Fluorine is a pale yellow gas and chlorine is a greenish-yellow gas.

What are the colors and states of bromine ($Br_{2}$) and iodine ($I_{2}$)?

Bromine is a brown gas and iodine is a purplish-black solid.

Why do the boiling point (bp) and melting point (mp) increase when going down Group 17?

1. The size of the molecule increases. 2. The force of attraction between molecules becomes stronger. 3. More heat is needed to overcome the force.

Explain why the reactivity of elements decreases when going down Group 17.

The atomic size increases, meaning the distance between the nucleus and valence electron is larger, causing the force of attraction to become weaker and reducing the tendency to accept electrons.

Why is chlorine ($Cl_{2}$) more reactive than bromine ($Br_{2}$)?

Chlorine has a smaller atomic size, so the distance between the nucleus and valence electron is closer, making the force of attraction stronger and increasing the tendency to accept electrons.

What is a neutralisation reaction?

A reaction where an acid reacts with a base to form a salt + water ($\text{Acid} + \text{Base} \rightarrow \text{Salt} + \text{Water}$).

Why is the reaction between an acid and a base called 'Neutralisation'?

Because the acid's $H^{+}$ and the base's $OH^{-}$ cancel each other out, making the solution neutral with a pH around $7$.

What is the definition of a Salt?

A compound made when the $H^{+}$ in an acid is replaced by a metal ion (such as $Na^{+}$, $K^{+}$, or $Ca^{2+}$).

According to Arrhenius Theory, what defines an acid and a base?

An acid produces hydrogen ions ($H^{+}$) or hydronium ions ($H_{3}O^{+}$) in water; a base produces hydroxide ions ($OH^{-}$) in water.

What is the limitation of the Arrhenius Theory?

It only works in water and does not account for bases that do not have $OH^{-}$ in their formula.

According to the Brønsted-Lowry Theory, what are acids and bases?

An acid is a proton ($H^{+}$ ion) donor, and a base is a proton ($H^{+}$ ion) acceptor.

What is the chemical equation for the Brønsted-Lowry reaction between $HCl$ and $NH_{3}$?

$$HCl + NH_{3} \rightarrow Cl^{-} + NH_{4}^{+}$$