Given below are two statements, one is labelled as Assertion $A$ and the other is labeled as Reason $R$
Assertion A : The alkali metals and their salts impart characteristic colour to reducing flame
Reason R : Alkali metals can be detected using flame tests
In the light of the above statements, choose the most appropriate answer from the options given below
Assertion A : The alkali metals and their salts impart characteristic colour to reducing flame
Reason R : Alkali metals can be detected using flame tests
In the light of the above statements, choose the most appropriate answer from the options given below
- $A$ is not correct but $R$ is correct
- Both $A$ and $R$ are correct but $R$ is NOT the correct explanation of $A$
- Both $A$ and $R$ are correct and $R$ is the correct explanation of $A$
- $A$ is correct but $R$ is not correct
The Correct Option is A
Solution and Explanation
Assertion A is incorrect. Alkali metals and their salts typically impart distinct colors to an oxidizing flame, not a reducing flame. When alkali metal salts are heated in a flame, they excite the metal ions, which then emit characteristic colors as they return to their ground state. These colors are observed in an oxidizing flame (such as that produced by a Bunsen burner with sufficient oxygen), not in a reducing flame, which lacks the necessary oxidizing conditions for such reactions to occur.
Reason R is correct. Flame tests are indeed a common and reliable method for identifying alkali metals and other metal ions based on the characteristic colors they emit when heated. For example, lithium produces a red flame, sodium a bright yellow flame, and potassium a lilac flame. This principle is widely used in qualitative analysis.
Top Questions on p -Block Elements
Method used for separation of mixture of products (B and C) obtained in the following reaction is:
- JEE Main - 2026
- Chemistry
- p -Block Elements
- Statement-I: An element ‘X’ of P-block forms a hydride H–X, which has the longest bond length, then element ‘X’ will have the shortest covalent radius.
Statement-II: An element ‘E’ of Group 15 forms hydride EH$_3$, that has least B.P. The maximum covalency of E is 4.
- JEE Main - 2026
- Chemistry
- p -Block Elements
- Given below are two statements:
Statement I: [CoBr₄]²⁻ ion will absorb light of lower energy than [CoCl₄]²⁻ ion.
Statement II: In [CoBr₄]²⁻ ion, the energy separation between the two set of d-orbitals is more than [CoCl₄]²⁻ ion.
In the light of the above statements, choose the correct answer from the options given below :- JEE Main - 2026
- Chemistry
- p -Block Elements
- Given below are two statements: Statement I: Elements \(X\) and \(Y\) are the most and least electronegative elements, respectively, among \(N\), \(As\), \(Sb\) and \(P\). The nature of the oxides \(X_2O_3\) and \(Y_2O_3\) is acidic and amphoteric, respectively. Statement II: \(BCl_3\) is covalent in nature and gets hydrolysed in water. It produces \([B(OH)_4]^-\) and \([B(H_2O)_6]^{3+}\) in aqueous medium. In the light of the above statements, choose the correct answer from the options given below:
- JEE Main - 2026
- Chemistry
- p -Block Elements
- For \( P \), the incorrect statement is:
- JEE Main - 2026
- Chemistry
- p -Block Elements
Questions Asked in JEE Main exam
- The sum of all possible values of \( n \in \mathbb{N} \), so that the coefficients of \(x, x^2\) and \(x^3\) in the expansion of \((1+x^2)^2(1+x)^n\) are in arithmetic progression is :
- JEE Main - 2026
- Integration
- In a microscope of tube length $10\,\text{cm}$ two convex lenses are arranged with focal lengths $2\,\text{cm}$ and $5\,\text{cm}$. Total magnification obtained with this system for normal adjustment is $(5)^k$. The value of $k$ is ___.
- JEE Main - 2026
- Optical Instruments
Which one of the following graphs accurately represents the plot of partial pressure of CS₂ vs its mole fraction in a mixture of acetone and CS₂ at constant temperature?
- JEE Main - 2026
- Organic Chemistry
- Let \( ABC \) be an equilateral triangle with orthocenter at the origin and the side \( BC \) lying on the line \( x+2\sqrt{2}\,y=4 \). If the coordinates of the vertex \( A \) are \( (\alpha,\beta) \), then the greatest integer less than or equal to \( |\alpha+\sqrt{2}\beta| \) is:
- JEE Main - 2026
- Coordinate Geometry
- Three charges $+2q$, $+3q$ and $-4q$ are situated at $(0,-3a)$, $(2a,0)$ and $(-2a,0)$ respectively in the $x$-$y$ plane. The resultant dipole moment about origin is ___.
- JEE Main - 2026
- Electromagnetic waves
Concepts Used:
P-Block Elements
- P block elements are those in which the last electron enters any of the three p-orbitals of their respective shells. Since a p-subshell has three degenerate p-orbitals each of which can accommodate two electrons, therefore in all there are six groups of p-block elements.
- P block elements are shiny and usually a good conductor of electricity and heat as they have a tendency to lose an electron. You will find some amazing properties of elements in a P-block element like gallium. It’s a metal that can melt in the palm of your hand. Silicon is also one of the most important metalloids of the p-block group as it is an important component of glass.
P block elements consist of:
- Group 13 Elements: Boron family
- Group 14 Elements: Carbon family
- Group 15 Elements: Nitrogen family
- Group 16 Elements: Oxygen family
- Group 17 Elements: Fluorine family
- Group 18 Elements: Neon family