Acid-Base Reactions with Metals

What is the first step when checking the odour of cloth strips?

What is used to test the change in odour in the experiment?

Which of the following can potentially be used as an olfactory indicator?

In Activity 2.3, what acid is initially used in the test tube?

What material is added to the acid in the test tube in Activity 2.3?

In Activity 2.3, the gas evolved is passed through which solution?

What is used to test the gas-filled bubble?

What is the primary caution mentioned at the beginning of Activity 2.3?

Besides sulfuric acid, which of the following acids is also used in a similar activity?

What do you observe on the surface of zinc granules when they react with dilute sulfuric acid?

Why is it important to rinse the cloth strips with water before checking their odour again?

What is the purpose of using dilute solutions of vanilla essence and clove oil in the experiment with acids and bases?

What does a change in odour of vanilla essence or clove oil when reacted with an acid or a base indicate?

In Activity 2.3, what is the function of passing the evolved gas through a soap solution?

What does the burning of a gas-filled bubble indicate about the gas that was produced in Activity 2.3?

What is the expected outcome when a burning candle is brought near a bubble filled with hydrogen gas?

What is the purpose of repeating Activity 2.3 with different acids like HCl, HNO3, and CH3COOH?

What does it mean if the observations in Activity 2.3 are different when using HCl compared to CH3COOH?

If the reaction between an acid and zinc granules produces a gas, what general type of chemical reaction is taking place?

Considering the activities performed, what is the most accurate conclusion about olfactory indicators?

If the odour of clove oil completely disappears in a NaOH solution, but remains unchanged in HCl, what can be concluded about clove oil?

Suppose a student performs Activity 2.3 but forgets to use the soap solution. What direct observation would they likely miss?

In Activity 2.3, if the evolved gas extinguishes a burning candle with a 'pop' sound, which alternative gas could produce a similar result?

When testing the odours of vanilla essence after reacting with HCl and NaOH, a control sample of vanilla essence is needed. What is the primary purpose of this control?

Why is it essential to use dilute solutions of acids and bases when testing olfactory indicators, rather than concentrated ones?

In Activity 2.3, if copper granules were used instead of zinc, what would be the most likely observation?

A student notes that the reaction of zinc with hydrochloric acid (HCl) produces a different rate of bubble formation compared to acetic acid (CH3COOH). What inference can be drawn?

If, after reacting an olfactory indicator with an acid, a base is added and the original odour returns, what does this suggest about the reaction?

Consider a scenario where a student uses a different soap solution in Activity 2.3, and no bubbles form despite the gas being produced. What is the most likely explanation?

In a modified Activity 2.3, if a drying tube containing anhydrous calcium chloride ($CaCl_2$) is placed between the reaction vessel and the soap solution, what specific aspect of the evolved gas is being addressed?

Consider a scenario where, after reacting vanilla essence with dilute HCl, the resulting solution is meticulously neutralized with $Ca(OH)_2$ until pH 7 is achieved. If the original vanilla scent does not return, which complex phenomenon MOST likely accounts for this observation?

In Activity 2.3, if the evolved gas is passed through a solution of lead(II) acetate instead of soap solution, and a black precipitate forms, which of the following inferences is MOST accurate regarding the composition of the evolved gas?

While performing Activity 2.3 with $HNO_3$, a brown gas is observed evolving along with the primary gas. What is the MOST probable explanation for the formation of this brown gas?

Assume that in a modified Activity 2.3, the evolved gas is collected over water before testing its flammability. If the 'pop' sound upon ignition is significantly diminished compared to the standard procedure, what is the MOST likely reason for this?

Suppose a student uses copper turnings instead of zinc granules in Activity 2.3 with dilute sulfuric acid. After a prolonged period, no gas evolution is observed. If a small amount of concentrated nitric acid is then added to the mixture, and gas evolution begins, which species is MOST likely being produced, and why?

If during the testing of olfactory indicators, a student observes that both vanilla essence and clove oil exhibit altered odours in acidic conditions (dilute HCl) but no noticeable change in basic conditions (dilute NaOH), what inference can be BEST drawn?

In a variation of Activity 2.3, a redox indicator such as methylene blue is added to the sulfuric acid before the addition of zinc granules. If the solution changes from blue to colourless during the reaction, what is this MOST indicative of within the context of the experiment?

Suppose Activity 2.3 is conducted in a closed system, and the pressure is continuously monitored. If the pressure increases initially but then plateaus despite the continued addition of zinc granules, what is the MOST likely explanation for this phenomenon?

When testing the flammability of the gas evolved in Activity 2.3, a student observes that the 'pop' sound is followed by a faint yellow flame instead of a clean blue flame. What does this MOST likely indicate about the purity of the gas?

In a meticulously controlled experiment based on Activity 2.3, the rate of hydrogen gas evolution from the reaction of zinc with various concentrations of dilute $H_2SO_4$ is measured. If the data are plotted according to the Eyring equation, what kinetic parameters can MOST accurately be determined from the slope and intercept of the resulting linear plot?

What is the immediate next step after rinsing the cloth strips with water in the context of odour testing?

What should be done immediately after adding a few drops of dilute vanilla essence to test tubes containing dilute HCl and NaOH solutions?

Which of the following is NOT explicitly mentioned as being tested for its olfactory indicator properties?

In Activity 2.3, what is the purpose of passing the evolved gas through a soap solution?

What is the expected observation when zinc granules react with dilute sulfuric acid?

What is the primary reason for repeating Activity 2.3 with different acids, such as HCl, $HNO_3$, and $CH_3COOH$?

During the reaction of zinc granules with dilute sulfuric acid, what does the formation of bubbles in the soap solution directly indicate?

If the odour of vanilla essence diminishes in dilute HCl but intensifies in dilute NaOH, what can be inferred?

Suppose that in Activity 2.3, after adding dilute sulfuric acid to zinc granules, no gas is evolved even after several minutes. Which of the following is the MOST probable reason, assuming the reagents are fresh?

In a modified version of Activity 2.3, the evolved gas is collected, and its molar mass is experimentally determined to be approximately 2 g/mol. However, when this gas is mixed with air and ignited, it burns with an orange, sooty flame instead of a clean blue flame, and analysis reveals traces of $SO_2$. What is the MOST likely explanation for the observed discrepancy?

What is the purpose of shaking the test tubes after adding vanilla essence to dilute HCl and NaOH solutions?

In Activity 2.3, what is the immediate observation when dilute sulfuric acid is added to zinc granules?

Why is it important to test the evolved gas from the reaction between acids and zinc granules using a burning candle?

What is the main reason for repeating Activity 2.3 with different acids like HCl, $HNO_3$, and $CH_3COOH$?

Which of the following is a crucial safety precaution for Activity 2.3?

What observation would confirm that the gas evolved from the reaction of zinc and sulfuric acid is hydrogen?

Why are vanilla essence and clove oil useful as olfactory indicators?

If no bubbles form in the soap solution during Activity 2.3, despite adding zinc to sulfuric acid, what is the MOST likely reason?

Suppose you perform Activity 2.3 with zinc and dilute hydrochloric acid (HCl) and the resulting gas is collected in a balloon. If this balloon is then placed near a strong electromagnetic field, what, if anything, would you expect to observe? (Assume ideal conditions).

A student performs Activity 2.3 using zinc granules and dilute sulfuric acid but finds that the reaction proceeds very slowly, even with freshly prepared acid. Upon adding a few drops of copper sulfate solution ($CuSO_4$) to the reaction mixture, the rate of hydrogen gas evolution significantly increases. Which of the following mechanisms BEST explains this observation?