The question asks why a magnesium ribbon needs to be cleaned before burning. This relates to the chemical reactivity of metals with atmospheric components.
C) To remove oxide layer. This layer prevents or slows down the burning of magnesium, so removing it ensures a proper and vigorous reaction.
A balanced chemical equation adheres to the Law of Conservation of Mass, stating that the number of atoms of each element must be the same on both the reactant and product sides of the equation. To check if an equation is balanced, count the atoms of each element on both sides.
B) \( \text{Zn} + \text{H}_2\text{SO}_4 \to \text{ZnSO}_4 + \text{H}_2 \)
This equation is balanced because the number of atoms of each element (Zn, H, S, O) is equal on both the reactant and product sides.
The question asks to identify the type of chemical reaction represented by the equation: \( \text{CaO} + \text{H}_2\text{O} \rightarrow \text{Ca(OH)}_2 \). We need to analyze the reactants and products to determine how they combine or rearrange.
B) Combination — This is correct because Calcium Oxide and Water combine to form a single product, Calcium Hydroxide. This is a classic example of a combination reaction where two or more substances react to form a single new substance.
The question asks to identify a reaction where heat is absorbed. Such reactions are known as endothermic reactions. We need to evaluate each option to determine whether it involves the absorption or release of heat.
Correct Option: C) Photosynthesis is a process where plants absorb light energy (a form of heat/electromagnetic radiation) to convert carbon dioxide and water into glucose and oxygen. This makes it an endothermic reaction.
The question asks to identify a decomposition reaction among the given options. A decomposition reaction is a type of chemical reaction where a single compound breaks down into two or more simpler substances. This is typically represented as \( \text{AB} \rightarrow \text{A} + \text{B} \).
Based on the analysis, only option B represents a decomposition reaction.
Correct Option: B) \( 2\text{AgCl} \rightarrow 2\text{Ag} + \text{Cl}_2 \). In this reaction, silver chloride (a single compound) decomposes into silver and chlorine gas (two simpler substances). This is a classic example of a photodecomposition reaction, where light energy causes the breakdown.
UPSC - 2023
The question asks about the application of 'Microsatellite DNA'. To answer this, one needs to understand what microsatellite DNA is and its primary uses in biological studies.
Correct Option: A) Studying the evolutionary relationships among various species of fauna