MCQ 121
What is the byproduct of the reaction between an acid and a metal?
A) Water
B) Salt
C) Oxygen
D) Carbon dioxide
Answer: B) Salt.
Explanation: The reaction between an acid and a metal typically produces a salt and hydrogen gas.
MCQ 122
What does the term “molarity” refer to?
A) The volume of a solution
B) The amount of solute per liter of solution
C) The mass of solute in grams
D) The concentration of a gas
Answer: B) The amount of solute per liter of solution.
Explanation: Molarity is defined as the number of moles of solute divided by the volume of solution in liters.
MCQ 123
Which of the following is an indicator of a chemical change?
A) Change in temperature
B) Change in shape
C) Change in mass
D) Change in size
Answer: A) Change in temperature.
Explanation: A change in temperature can indicate that a chemical reaction has occurred, especially if it releases or absorbs heat.
MCQ 124
What is the main characteristic of a chemical equation?
A) It only shows reactants.
B) It must be balanced.
C) It can be written in any order.
D) It ignores states of matter.
Answer: B) It must be balanced.
Explanation: A chemical equation must be balanced to satisfy the Law of Conservation of Mass.
MCQ 125
Which of the following gases is produced during the reaction of vinegar with baking soda?
A) Hydrogen
B) Oxygen
C) Carbon dioxide
D) Nitrogen
Answer: C) Carbon dioxide.
Explanation: The reaction of vinegar (acetic acid) with baking soda (sodium bicarbonate) produces carbon dioxide gas.
MCQ 126
What is the function of a catalyst in a chemical reaction?
A) To change the reaction products
B) To increase the activation energy
C) To speed up the reaction without being consumed
D) To slow down the reaction
Answer: C) To speed up the reaction without being consumed.
Explanation: A catalyst increases the rate of a reaction by lowering the activation energy and is not consumed in the process.
MCQ 127
In which type of reaction does one element replace another in a compound?
A) Synthesis
B) Double replacement
C) Decomposition
D) Single replacement
Answer: D) Single replacement.
Explanation: In a single replacement reaction, one element replaces another in a compound.
MCQ 128
What does a neutral pH of 7 indicate?
A) Basic solution
B) Acidic solution
C) Neither acidic nor basic
D) Very acidic
Answer: C) Neither acidic nor basic.
Explanation: A pH of 7 indicates a neutral solution, meaning it is neither acidic nor basic.
MCQ 129
Which of the following represents a decomposition reaction?
A) 2H₂ + O₂ → 2H₂O
B) 2NaCl → 2Na + Cl₂
C) NH₃ + HCl → NH₄Cl
D) C + O₂ → CO₂
Answer: B) 2NaCl → 2Na + Cl₂.
Explanation: A decomposition reaction involves a single compound breaking down into two or more simpler products.
MCQ 130
What is produced when an alkali metal reacts with water?
A) Metal oxide
B) Salt and hydrogen
C) Acid
D) Hydroxide and hydrogen
Answer: D) Hydroxide and hydrogen.
Explanation: The reaction of alkali metals with water produces metal hydroxides and hydrogen gas.
Leave a comment