Are you a student preparing for your chemistry exams? Do you need guidance on important practical questions for the 12th class Lahore board exams in 2018? Well, you’re in luck! In this article, we will dive straight into the most crucial practical questions, providing detailed solutions to help you ace your exams. Whether you’re struggling with experiments or need a refresher on specific topics, these practical questions will ensure you are well-prepared. So, let’s explore the chemistry 12th class Lahore board important practical question 2018 together!
Chemistry 12th Class Lahore Board Important Practical Questions 2018
Chemistry is a fascinating subject that explains the composition, properties, and behavior of matter. Practical experiments are an essential component of the chemistry curriculum, allowing students to apply theoretical knowledge, develop scientific skills, and enhance their understanding of chemical concepts. In this article, we will explore some important practical questions from the 2018 Chemistry exam for 12th class students under the Lahore Board. These questions will cover various topics and provide valuable insights for students preparing for their practical exams.
Aim and Objectives
Before we dive into the specific questions, it’s important to understand the aims and objectives of practical experiments in the 12th class Chemistry curriculum. The practical component of the syllabus aims to:
- Develop practical skills such as measuring, observing, and recording experimental data.
- Apply theoretical knowledge to real-world situations.
- Enhance critical thinking and problem-solving abilities.
- Promote teamwork and collaboration among students.
- Provide hands-on experience to reinforce theoretical concepts.
Question 1: Preparation of Standard Solution
In this question, students were required to prepare a standard solution of sodium carbonate (Na2CO3). The aim of the experiment was to determine the concentration of the given solution accurately. The procedure involves the following steps:
- Weigh a predetermined amount of sodium carbonate and dissolve it in distilled water.
- Transfer the solution to a volumetric flask and add distilled water to reach the graduation mark.
- Mix the solution thoroughly by inverting the flask several times.
- Use the prepared standard solution for further experiments and calculations.
The practical question evaluates the student’s ability to handle precision instruments, perform calculations, and prepare accurate solutions.
Question 2: Determination of pH of Different Solutions
This question focuses on the measurement of pH using different indicators and pH meters. The objective is to determine the acidity or alkalinity of given solutions. Students apply the following steps:
- Label a series of test tubes and fill them with the given solutions.
- Add a few drops of different indicators to each test tube and note the color change.
- Compare the colors obtained with the corresponding pH scale to determine the pH value.
- Repeat the experiment using a pH meter to obtain more accurate results.
This practical question assesses the student’s understanding of pH, indicators, and their proficiency in using pH measuring instruments.
Question 3: Identification of Organic Compounds
This question requires students to identify the given organic compounds using various tests and observations. The compounds may include aldehydes, ketones, alcohols, and carboxylic acids. The experimental procedure involves:
- Performing the iodoform test to identify compounds containing the CH3CO- group.
- Testing for the color change in Schiff’s reagent to detect the presence of aromatic aldehydes.
- Heating the compounds to check the evolution of carbon dioxide gas, indicating the presence of carboxylic acids.
- Performing the oxidation test to differentiate between primary and secondary alcohols.
This practical question challenges the student’s knowledge of organic functional groups and their ability to conduct relevant tests for identification.
Question 4: Determination of Enthalpy Change
In this question, students are required to measure the enthalpy change during a chemical reaction using a calorimeter. The procedure involves:
- Set up a calorimeter by placing a known mass of water in a container.
- Measure the initial temperature of the water and the reactant solution.
- Mix the reactant solution with the water and carefully monitor the temperature change.
- Calculate the enthalpy change using the data obtained and apply relevant formulas.
This practical question assesses the student’s understanding of thermochemistry, heat transfer, and their ability to use calorimetry to measure enthalpy changes.
Question 5: Electrolysis of Water
In this question, students perform the electrolysis of water to observe the production of hydrogen and oxygen gases. The procedure involves the following steps:
- Set up a simple electrolytic cell with two electrodes (a cathode and an anode).
- Add a small amount of sulfuric acid to water to facilitate the electrolysis process.
- Apply a direct current to the electrodes and observe the gases being evolved.
- Collect the gases separately and test their combustibility.
This practical question enables students to understand the concept of electrolysis, the nature of gases evolved, and their ability to perform the experiment safely.
Practical experiments play a crucial role in the learning and assessment of chemistry in the 12th class Lahore Board curriculum. Through these experiments, students develop important scientific skills, enhance their understanding of theoretical concepts, and apply their knowledge to real-world situations. The questions discussed in this article provide students with a comprehensive understanding of the practical component of the 2018 Chemistry exam. By thoroughly preparing for these questions, students can effectively demonstrate their practical knowledge and excel in their exams.
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Frequently Asked Questions
What are some important practical questions for the Chemistry 12th class Lahore Board in 2018?
Below are some important practical questions for the Chemistry 12th class Lahore Board in 2018:
How can we determine the molar mass of a volatile liquid using the Victor Meyer method?
The molar mass of a volatile liquid can be determined using the Victor Meyer method. In this method, a known mass of the liquid is vaporized and the volume of the vapor obtained is measured at a known temperature and pressure. By applying the ideal gas equation, the molar mass of the substance can be calculated.
What is the procedure to measure the boiling point of a liquid using a Beckmann thermometer?
To measure the boiling point of a liquid using a Beckmann thermometer, first, the Beckmann thermometer is set up in a boiling tube containing the liquid. The initial reading on the thermometer is noted. Then, the liquid is heated until it starts boiling, and the final reading on the thermometer is recorded. The difference between the initial and final readings gives the boiling point of the liquid.
How can we identify the functional groups present in organic compounds using chemical tests?
Chemical tests can be used to identify the functional groups present in organic compounds. For example, the bromine water test is used to identify the presence of an alkene or alkyne group, the Fehling’s solution test is used to identify the presence of an aldehyde or ketone group, and the Lucas test is used to determine the presence of an alcohol group. These tests involve specific reactions with the functional groups, leading to observable color changes or precipitation.
Chemistry 12th class Lahore board important practical question 2018 covers essential concepts that students must focus on for their exams. The practical questions provide hands-on experience and reinforce theoretical knowledge. These questions enable students to apply their understanding of chemical reactions, identification of compounds, and laboratory techniques. By practicing these questions, students can enhance their problem-solving skills and gain confidence. It is crucial for students to familiarize themselves with these practical questions to excel in their 12th class chemistry exams under the Lahore board.