Question

Listed are several pairs of substances. For some pairs, one or both members of the pair react individually with water to produce a gas. For others, neither member of the pair reacts with water. The pair for which each member reacts with water and yields the same gaseous product is (a) \(\mathrm{Al}(\mathrm{s})\) and \(\mathrm{Ba}(\mathrm{s}) ;\) (b) \(\mathrm{Ca}(\mathrm{s})\) and \(\mathrm{CaH}_{2}(\mathrm{s}) ; \quad(\mathrm{c}) \quad \mathrm{Na}(\mathrm{s})\) and \(\mathrm{Na}_{2} \mathrm{O}_{2}(\mathrm{s}) ; \quad\) (d) \(\mathrm{K}(\mathrm{s})\) and \(\mathrm{KO}_{2}(\mathrm{s}) ;(\mathrm{e}) \mathrm{NaHCO}_{3}(\mathrm{s})\) and \(\mathrm{HCl}(\mathrm{aq}).\)

Short answer

The pair which each member reacts with water and yields the same gaseous product is \(\mathrm{Ca}(\mathrm{s})\) and \( \mathrm{CaH}_{2}(\mathrm{s}) \).

Step-by-step solution

Analyze pairs and their reactions with water

First, consult the chemical reactions of each substance with water. For example, Al(s) reacts to form \(\mathrm{Al(OH)}_{3}(s)\) and \(\mathrm{H}_{2}(g)\). Also, Ba(s) reacts to form \(\mathrm{Ba(OH)}_{2}(aq)\) and \(\mathrm{H}_{2}(g)\). Analyze similar reactions for all other pairs.

Identify pairs that produce the same gaseous product

The next step involves identifying which pairs produce the same gaseous product upon reaction. For instance, \(\mathrm{Al}(\mathrm{s})\) and \(\mathrm{Ba}(\mathrm{s})\) both produce \(\mathrm{H}_{2 }(g)\) as the gaseous product.

Validate the given pairs

Now validate the given pairs which fulfill the conditions of the problem. The pair \(\mathrm{Ca}(\mathrm{s})\) and \( \mathrm{CaH}_{2}(\mathrm{s}) \) are reacting with water to produce the same gaseous product, which is \(\mathrm{H}_{2}(g).\)

Key concepts

Chemical Reactions

Chemical reactions involve the transformation of substances into new forms through a process of breaking and forming bonds. Reactions with water are quite common in chemistry. When a metal reacts with water, it often forms a metal hydroxide and hydrogen gas is released. This is a type of single replacement reaction where a more active substance displaces another in a compound, leading to the formation of new products.

In the exercise, we looked at several different substances reacting with water. For instance, aluminum (A\(\mathrm{l}\)) reacts with water to form aluminum hydroxide (\(\mathrm{Al(OH)}_{3}\)) and hydrogen gas (\(\mathrm{H}_2\)). Similarly, barium (\(\mathrm{Ba}\)) reacts with water to produce barium hydroxide (\(\mathrm{Ba(OH)}_{2}\)) and hydrogen gas.

The fundamental factors influencing these reactions include the reactivity of the metals involved and the conditions of the reaction, such as temperature and concentration of reactants.

Gaseous Products

Gaseous products are often formed when solids or liquids undergo chemical reactions, particularly with water. For reactions involving metals, hydrogen gas (\(\mathrm{H}_2\)) is a common gaseous product. In the reaction process, metals displace hydrogen from water molecules, releasing it in its gaseous form.

In the problem, both aluminum and barium produce hydrogen gas when they react with water. This makes hydrogen the common outcome for many metal-water reactions.

Gases produced in chemical reactions can have various effects. They might result in pressure changes in closed systems or cause effervescence in open systems. Understanding gaseous products helps predict and control the nature of reactions, including any possible hazards associated with gas production.

Reaction Analysis

Analyzing reactions involves studying the reactants, products, and the conditions under which reactions occur. In this exercise, the task is to evaluate pairs of substances to see if both members of a pair react with water to yield the same gaseous product.

The step-by-step solution shows that analyzing reactions requires identifying all possible products and comparing them across different scenarios. For instance, when considering calcium (\(\mathrm{Ca}\)) and calcium hydride (\(\mathrm{CaH}_{2}\)), both react with water to produce hydrogen gas.

Reaction analysis entails not only identifying similar gaseous products but also validating conditions such as reaction temperature or catalysts that may influence the outcome. Additionally, careful observation and recording of details are crucial to ensure that the analysis is accurate and reliable.