IB myp 4-5 Chemistry – Practice Questions- All Topics
Topic :Types of chemical reaction-Electrochemical cells
Topic :Types of chemical reaction-Weightage : 21 %
All Questions for Topic :acids and bases,neutral solutions,acid/base reactions,$\mathrm{pH}$ and indicators,formation of salts,uses of salts,redox reactions,reactivity series,extraction of metals and corrosion,electrochemical cells
Question:
Why do negatively charged anions from the salt bridge move into the anode cell and positively charged cations move into the cathode cell when the half-cells are connected?
▶️Answer/Explanation
Ans: Anions from the salt bridge move into the anode cell to maintain charge balance as electrons are lost from the anode into the external circuit. Cations from the salt bridge move into the cathode to counter balance the electrons that move into the cathode from the external circuit.
Question:
Draw a labelled diagram of the apparatus and chemicals used in one of the tests you performed. Ensure that you label the polarity of the electrodes, the voltmeter, the anode and cathode, the direction of electron flow in the wires and the salt bridge.
▶️Answer/Explanation
Ans: Identify the anode and cathode cell; identify the composition of the electrolyte in each cell and the molarity; label the polarity of the electrodes; draw the symbol for a voltmeter in the external circuit; identify the direction of the electron flow in the external circuit; nominate and name the electro– lyte for the salt bridge and state its molarity.
Question:
Construct half-equations for each of the reactions that occurred at the anode and cathode.
▶️Answer/Explanation
Ans: Half reactions should be charged balanced (states of matter not required).