Common Laboratory Apparatus and Equipments — Important Questions

To expel poisonous gases and fumes so students can work safely for longer periods

Step 1: Many chemical reactions produce harmful gases and toxic fumes as by-products. Step 2: If these gases accumulate inside the laboratory, they can be inhaled by students and teachers, causing health problems. Step 3: Exhaust fans are placed near the ROOF because most hot gases and fumes are lighter than air and rise upward. Step 4: By expelling these gases from near the roof, fresh air is drawn in from below, creating a safe working environment. Step 5: While cooling and humidity control (Options A and D) are secondary benefits, the PRIMARY reason stated in the chapter is to expel poisono

Mortar and Pestle

Step 1: The task requires grinding (crushing) a solid into a fine powder — a mechanical process. Step 2: A Crucible is used for strong heating of substances, not for grinding. Tongs are used to pick up hot apparatus — neither is suitable for grinding. Step 3: An Evaporating Dish is used to evaporate liquids, and a Glass Rod is used to stir solutions — not for grinding solids. Step 4: A Watch Glass is used like a small evaporating dish or to cover beakers; a Spatula transfers small amounts of solid — again, not for grinding. Step 5: The Mortar (the bowl-shaped container) and Pestle (the hand to

Immediately wash the affected area with cold running water and report to the teacher

Step 1: A corrosive chemical causes chemical burns by reacting with skin tissue — immediate action is critical to minimize damage. Step 2: The FIRST action must be to dilute and remove the chemical by washing with COLD RUNNING WATER continuously. Running water is important because still water can become concentrated with the chemical. Step 3: Applying a neutralising chemical (Option A) seems logical but is DANGEROUS — it can cause an additional chemical reaction on the skin, releasing heat and causing more harm. Step 4: Wiping with a dry cloth (Option C) only spreads the chemical over a larger

Thistle Funnel

Step 1: A regular Glass Funnel is cone-shaped and is used for filtering or transferring liquids into open containers — it cannot be used in a controlled, closed system easily. Step 2: A Thistle Funnel has a unique design — it has a bulb-shaped reservoir at the top and a long stem that can be inserted into a stopper in a closed flask. Step 3: This design allows liquid (such as acid) to be added slowly and in a controlled manner into a closed apparatus during gas-generation experiments. Step 4: A Measuring Cylinder measures volume but does not transfer liquids into closed systems. Step 5: A Deli