Question

Silica reacts with \(\mathrm{Mg}\) to form a magnesium compound X. X reacts with dilute HCl and forms Y. Y is: (a) \(\mathrm{MgCl}_{2}\) (b) \(\mathrm{MgO}\) (c) \(\mathrm{SiCl}_{4}\) (d) \(\mathrm{Mg} \mathrm{SiO}_{3}\)

Short answer

Y is MgCl extsubscript{2}, option (a).

Step-by-step solution

Identify the Reaction Products of Silica and Magnesium

Silica, which is silicon dioxide ( SiO_2 ), reacts with magnesium ( ext{Mg}) to form magnesium silicate ( ext{Mg}_2 ext{SiO}_4). This newly formed product is known as compound X.

Reaction of Compound X with Dilute HCl

When magnesium silicate ( ext{Mg}_2 ext{SiO}_4) is reacted with dilute HCl ( ext{HCl}), it results in the formation of magnesium chloride ( ext{MgCl}_2) and silicic acid or water. Therefore, compound Y is  ext{MgCl}_2.

Choose the Correct Option

According to the products formed in Step 2, compound Y is  ext{MgCl}_2. From the given choices, choose the option that corresponds to  ext{MgCl}_2, which is option (a).

Key concepts

Silica and Magnesium Reaction

In the vast world of inorganic chemistry, understanding the interaction between different elements is crucial. One notably interesting reaction is between silica, or silicon dioxide ( \(\text{SiO}_2\) ), and magnesium ( \(\text{Mg}\) ). Both these elements are found abundantly on Earth. Silica is a compound made up of silicon and oxygen. Together, they form a +4 and -2 oxidation state, respectively. Magnesium, a metal, is highly reactive with non-metals.

When magnesium is introduced to silica under the right conditions, they react to form magnesium silicate ( \(\text{Mg}_2\text{SiO}_4\) ). This compound is a type of magnesium compound, which plays a pivotal role in this reaction sequence. The process itself is fascinating, as magnesium atoms replace the silicon in silica due to their high reactivity, creating the compound we identify as X in this context.

Magnesium Compounds

Magnesium is a versatile element, forming a variety of compounds that are widely used in various industries. Once it reacts with silica, as mentioned, it forms magnesium silicate ( \(\text{Mg}_2\text{SiO}_4\) ). This is just one of many potential magnesium compounds.

Magnesium itself is a silvery metal, but its compounds exhibit different properties. For example:

• Magnesium Oxide (\(\text{MgO}\)): Used in refractory materials and as an insulator in electric cables.
• Magnesium Hydroxide (\(\text{Mg(OH)}_2\)): Often used as an antacid and laxative.
• Magnesium Chloride (\(\text{MgCl}_2\)): Plays a role in dust control and ice melting.

For students, understanding the formation and use of different magnesium compounds is important, as it shows the versatility and industrial relevance of magnesium in chemistry.

Reaction with Hydrochloric Acid

In chemical reactions, the interaction between acids and bases can lead to interesting compound formations and transformations. Here, when magnesium silicate ( \(\text{Mg}_2\text{SiO}_4\) ) is introduced to dilute hydrochloric acid ( \(\text{HCl}\) ), a new reaction takes place.

The \(\text{HCl}\) reacts with \(\text{Mg}_2\text{SiO}_4\) to produce magnesium chloride ( \(\text{MgCl}_2\) ) and silicic acid, or sometimes just water if the silicic acid further decomposes. This showcases how hydrochloric acid can serve as a useful reagent for breaking down more complex materials into simpler compounds. It’s a common technique in labs when the goal is to isolate certain elements or analyze complex compounds further. Students should focus on understanding the role of acids like \(\text{HCl}\) in promoting such reactions.

Magnesium Chloride Formation

Magnesium chloride ( \(\text{MgCl}_2\) ) is a salt that emerges as a primary product in several chemical reactions involving magnesium and various acids. It is particularly highlighted in this sequence of reactions as compound Y, which results from the reaction of magnesium silicate with hydrochloric acid.

The significance of \(\text{MgCl}_2\) in practical applications is vast. Not only is it used in ice control and dust control, but it also holds importance in the industrial sector for the production of magnesium metal in a process called the "Dow process". Additionally, its role in water purification systems showcases its utility.

For students, recognizing the conditions under which \(\text{MgCl}_2\) is formed, as well as its multiple uses, offers insights into its chemical and practical relevance.