Question

Match the column I with column II and mark the appropriate choice. \begin{tabular}{|l|l|l|l|} \hline \multicolumn{2}{|c|} { Column I } & \multicolumn{2}{c|} { Columi II = } \\\ \hline (A) & \(\mathrm{Na}\) & (i) & Crimson red \\ \hline (B) & \(\mathrm{K}\) & (ii) & Yellow \\ \hline (C) & \(\mathrm{Sr}\) & (iii) & Apple green \\ \hline (D) & \(\mathrm{Ba}\) & (iv) & Violet \\ \hline \end{tabular} (a) (A) \(\rightarrow(i),(B) \rightarrow(i i),(C) \rightarrow(i i i),(D) \rightarrow\) (iv) (b) \((\mathrm{A}) \rightarrow(\mathrm{ii}),(\mathrm{B}) \rightarrow(\mathrm{iv}),(\mathrm{C}) \rightarrow(\mathrm{i}),(\mathrm{D}) \rightarrow\) (iii) (c) \((\mathrm{A}) \rightarrow(\mathrm{iv}),(\mathrm{B}) \rightarrow\) (iii), (C) \(\rightarrow\) (ii), (D) \(\rightarrow\) (i) (d) (A) \(\rightarrow\) (iii), (B) \(\rightarrow\) (iv), (C) \(\rightarrow\) (i), (D) \(\rightarrow\) (ii)

Short answer

(A) \rightarrow (ii), (B) \rightarrow (iv), (C) \rightarrow (i), (D) \rightarrow (iii)

Step-by-step solution

Identify the significance of the columns

Column I lists chemical elements and Column II lists the colors emitted by flames of these elements when they are heated. This type of reaction is known as the flame test where different elements emit specific flame colors depending on their emission spectrum.

Match each element with its corresponding flame color

Match each element in Column I with the corresponding color it emits during a flame test based on known results:- Sodium (Na) is known to give a yellow color.- Potassium (K) gives a violet or lilac color.- Strontium (Sr) emits a crimson red color.- Barium (Ba) results in an apple green flame.

Compare matched pairs with options

Compare the matched pairs from Step 2 with the given options to identify the correct one.

Key concepts

Emission Spectrum

When we heat chemical elements, they exhibit an intriguing characteristic: they emit light at particular wavelengths, creating what is known as an emission spectrum. This process is akin to each element's unique fingerprint. Imagine each element crooning its own tune with a distinct pitch and rhythm; the emission spectrum embodies those unique songs in the form of light.

The reason behind this vivid luminescence lies in the electrons. When an element is heated, the energy absorbed by its electrons causes them to jump to higher energy levels. But these high-energy states are like tightrope walks for electrons; they can't hold their balance for long. So, they return to their original, lower energy levels, emitting the extra energy as light particles called photons.

These photons make up the emission spectrum of the element, displayed as distinct lines on a spectrometer. Significantly, the color of the light depends on the wavelength of these photons. When we know the characteristic emission spectrum of an element, we can use it to identify the element, just as detectives use fingerprints to identify individuals. That's the beauty of the emission spectrum: it's a dazzling detective tool in the world of chemistry!

Chemical Elements

At the heart of any flame test lies the chemical element being tested. Chemical elements are the building blocks of all matter in the universe. From the oxygen we breathe to the calcium in our bones, these elements are present in different combinations to form compounds that make up everything we see and touch.

Each chemical element has its own set of properties, including atomic number, atomic mass, and unique electron arrangements. It is this electron configuration that determines an element's chemical behavior, including the distinctive colors they emit when heated. This makes understanding chemical elements fundamental not just in chemistry, but in understanding the composition and behavior of the entire material world.

To enhance the grasp of elements, periodic tables are used, which cleverly classify and arrange elements based on similarities in their properties. This not only systematizes our knowledge but also hints at the relationships between different elements, guiding us in predicting how they might react and interact with each other.

Flame Colors

Let's delve into the kaleidoscope of hues that elements reveal under the flame test, collectively known as flame colors. Each element's electrons, when excited by heat, not only leap to higher energy levels but make their return journey in a jiffy. In doing so, they emit energy. The particular color we observe is a direct result of the energy change involved.

For instance, sodium ions emit a vivid yellow due to their emission of photons with a wavelength that corresponds to the yellow region of the light spectrum. This bright yellow is so distinct that even minute amounts of sodium can dominate the color of a flame. This is why sodium is used in street lamps that bathe our streets in a warm, yellow glow.

In a classroom or lab setting, students can perform a flame test to observe these colors and use the results to identify an unknown element or confirm the presence of specific elements in a compound. To assist students in making accurate matches, we can incorporate visual aids or charts showing the typical flame colors associated with common elements during a flame test. This practical application of colorimetry is not only visually striking but an excellent way to make elemental identification more engaging and memorable.