Halogen Hydrides - Check Meaning and Formula

Halogen hydrides, commonly referred to as hydrogen halides, are compound chemicals based on hydrogen—combinations of halogens, namely, fluorine, chlorine, bromine, iodine, and hydrogen. These compounds find broad applications in various industries besides being very important in the understanding of the chemistry of acid-base. For instance, hydrochloric acid is another primary input to a vast number of chemical reactions and industrial processes to which hydrogen chloride is heavily applied during either the initial production stage of the acid or as a fundamental active ingredient in many other processes such as metal cleaning and food processing, among others. Simultaneously, hydrofluoric acid is the similarly basic product of hydrogen fluoride since it enjoys very wide applicability, mainly in the glass etching and semiconductor industries.

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This Story also Contains

1. Physical Properties of Group 13 - 2
2. Relevance and Applications
3. Some Solved Examples
4. Summary

The comprehension of halogen hydrides is in understanding their physical and chemical properties, wherein both will give great variations depending on the halogen used. Such class compounds cater to colorless and gaseous behavior with other states at room temperature. This is due to the effect of molecular weight and the capability of hydrogen bonding. Their corruption in water and their acidity also vary, wherein some halogen hydride forms strong acids while others behave as weak acids.

The following essay is an attempt to explore the subject matter of halogen hydrides by taking into account the physical properties under two major parts. The first part will present very basic ideas associated with halogen hydrides, including definitions and essential features. The second will bring in the different varieties of halogen hydrides and their respective importance. The real-life application and relevance of the compounds in the academic and industrial fields will then be described very precisely.

Physical Properties of Group 13 - 1
Bayer halides (halogen hydrides) of group 13 -1 have several physical properties dependent on the molecular structure. The hydrogen halides belong to the gaseous. They are commonly colorless under standard conditions, Coloration can be highly variable but, with some exceptions, when hydrogen bromide is in the liquid state, nothing more than a light yellow can be attributed to the liquid, while the hydrogen iodide may have some purple color due to the presence of iodine vapor. The boiling and melting points of these compounds tend to increase with the molecular weight, reflecting increased van der Waals forces. For instance, the boiling point of hydrogen fluoride is 19.5°C, compared with hydrogen chloride far below -85°C, because of the extensive hydrogen bonding in HF, which significantly influences its physical state. On the other hand, although it is highly soluble in water, in contrast to the low solubility of all the halogen hydrides, hydrogen fluoride is a highly soluble gas in water, producing a weak hydrofluoric acid.

HF is a low boiling liquid due to intermolecular hydrogen bonding. The volatility order of these hydrides follows the given order:
HCl > HBr > HI > HF
Thus, the boiling point order would be the reverse of this order:
HF > HI > HBr > HCl

• As we move down the group, the bond length between the hydrogen and the halogen element increases. Thus, thermal stability, bond strength and dipole moment decrease down the group and follow the order given below:
  HF > HCl > HBr > HI
• As the bond length increases down the group, the bond dissociation energy decreases
• The reducing character and acidic strength of hydrides increase down the group.

Physical Properties of Group 13 - 2

There is one more specific chemical activity of all halogen hydrides in common that sets them apart from one another. If, in this case, hydrofluoric acid is known for its great strength of acidity and its ability is to even corrode glass. Strong acid hydrogen chloride of vast importance in industry is used in experiments with food and cleaning metals. There are also halides of bromine and iodine, for example, hydrogen bromide—HBr and hydrogen iodide—HI. These have reduced acidity and find many uses in chemical syntheses. In each case, however, the electronegativity of the halogen in such compounds is a general cause, and reactivity in the case of a compound is directly related to safety.

Relevance and Applications

Such halogen hydrides are of deep significance with multiple applications, underlining importance both for academic research and industry. From an industrial chemistry perspective, these compounds are key reagents in synthesis. For instance, hydrogen chloride finds applications in the processes of producing PVC—a pivotal plastic in construction and packaging. It is used in etching silicon wafers in semiconductor manufacture, a critical step in the process of making modern electronics.

In the academic field, the use of the halogen hydride is applied in explaining a number of keynote theories concerning molecular bonding, acid-base chemistry, and mechanisms of reaction. An understanding of some principles, for instance, solubility and ionic dissociation, among others, is gained from research on the behavior of the halogen hydrides in water. In addition, the incidence occasioned by means caused by these compounds has been subjected to constant review by scholars since they have an environmental effect. In this regard, special attention is paid to hydrofluoric acid, since it is poisonous and can pollute the groundwater. Therefore, this shall be the responsibility to handle and apply the halogen hydrides to ensure its safety in its use in various industries.

Recommended topic video on(Halogen Hydrides)

Some Solved Examples

Example 1
Question: In which of the following arrangements is the sequence not strictly according to the property written against it?
1) $( \text{CO}_2 < \text{SiO}_2 < \text{SnO}_2 < \text{PbO}_2 )$: increasing oxidizing power
2) $( \text{HF} < \text{HCl} < \text{HBr} < \text{HI} )$: increasing acid strength
3) $( \text{NH}_3 < \text{PH}_3 < \text{AsH}_3 < \text{SbH}_3$ : increasing basic strength
4) $( \text{B} < \text{C} < \text{O} < \text{N} )$: increasing first ionization enthalpy

Solution: The correct order of basic strength of the hydrides of Group 15 is $( \text{NH}_3 > \text{PH}_3 > \text{AsH}_3 > \text{SbH}_3 )$. Thus, option (3) is not strictly according to the property.

Example 2
Question: Which of the following has the highest $( \mathrm{pK_a} )$ value?
1) HI
2) HBr
3) HCl
4) HF

Solution: The order of $( \mathrm{pK_a} )$ values for these is $( \mathrm{HI < HBr < HCl < HF})$. Therefore, the highest $( \mathrm{pK_a} )$ value is for HF, making option (4) the correct answer.

Example 3
Question: Which of the following has the highest dipole moment?
1) HF
2) HCl
3) HBr
4) HI

Solution: The dipole moment of hydrides of halogens follows the order $( \text{HF} > \text{HCl} > \text{HBr} > \text{HI} )$. Hence, HF has the highest dipole moment, so the correct answer is option (1).

Summary

Halogen hydrides are very important chemical compounds that show significant chemical and physical features. Hence, we have now considered definitions offered, unusual, features, and differences in levels of acidity. We have also seen their ways of existence under real life's conditions as essential products in industrial activity and under study. One who has got acquainted with halogen hydrides is the student or worker in this sphere himself and feels the role of such compounds in chemistry and life activity in general.