Question

REACTION OF ACIDS AND BASES WITH METALS IN LAB ACTIVITY PROCEDURE

Answer 1

Procedure: To perform in real lab:

 Action of litmus solution with acid and base.

 

ExperimentObservationInferenceTake a little amount of blue and red litmus solutions separately in two test tubes. Add few drops of HCl to each test tube using a dropper.Blue litmus turns red.HCl is an acid having pH value below 7.Take a little amount of blue and red litmus solutions separately in two test tubes. Add few drops of NaOH to each test tube using a dropper.Red litmus turns blue.NaOH is an alkali having pH value more than 7.

 

 
The evolution of hydrogen gas can be seen by conducting the following experiments.

 

ExperimentObservationInferenceTake some pieces of zinc metal in a boiling tube. Add few drops of HCl into the boiling tube using a dropper. Then place a dropper with a fine jet on the mouth of the tube. Heat the boiling tube. Bring a burning matchstick near the mouth of the fine jet.A gas is evolved. It extinguishes the burning matchstick and burns itself with mild explosion and produces a popping sound.The gas evolved is hydrogen which burns with mild explosion.Take some pieces of zinc metal in a boiling tube. Add few drops of NaOH into the boiling tube using a dropper. Then place a dropper with a fine jet on the mouth of the tube. Heat the boiling tube. Bring a burning matchstick near the mouth of the fine jet.A gas is evolved. It extinguishes the burning matchstick and burns itself with mild explosion and produces a popping sound.The gas evolved is hydrogen which burns with mild explosion.

Action of HCl on solid sodium carbonate

ExperimentObservationInferenceTake a small quantity of solid sodium carbonate in a flask. Then add distilled water into it. Cork the flask with a double bore cork and insert a thistle funnel into the flask. Then place a beaker containing lime water near the flask. Then insert one end of the delivery tube into the flask and the other end into the beaker. Now add HCl into the flask through the thistle funnel and observe the change in colour of the lime water.A gas is evolved which turns lime water turns milky.The gas produced is carbon dioxide due to the action of HCl on Na2CO3, which turns lime water milky.

Action of NaOH on solid sodium carbonate

ExperimentObservationInference

Zinc metal (For Acid and Base)

To pour the sample into the test tube containing zinc metal, drag the beaker towards the test tube.To close the test tube, drag the single bored cork (in which a fine jet tube is inserted through the hole) towards the test tube.Click on the knob of the burner to turn it on.You can see that gas bubbles are evolved from the test tube.Now, drag the burning match stick over the fine jet tube.The flame dips out with a mild explosion.You can verify your result and can see the inference by clicking on the correct icon given under  ‘Result’.Click on the 'Reset' button to restart the test.

Solid Na2CO3 (For Base)

To pour sample into solid sodium carbonate, drag the beaker towards the test tube.To pour phenolphthalein into the mixture of solid sodium carbonate and the sample, drag the beaker towards the test tube.You can verify your result and can see the inference by clicking on the correct icon in the ‘Result’ part.Click on the ‘Reset’ button to redo the experiment.

Note: Click on the ‘HELP’ button to see the instructions.

Precautions:

Take small quantities of zinc, HCl and NaOH for their reaction, otherwise large amount of hydrogen produced may cause explosion.To hydrogen burning take a fine jet.Add HCl to Na2CO3, only when apparatus is made carefully airtight.NaOH and HCl are injurious, handle these chemicals carefully.

So, try out all and observe the changes………………

 

 

Answer 2

Activity to react metal with dilute acid

Explanation

Apparatus required :

Test tube

Tripod stand

Delivery tube

Water trough

Dropper

Cork

Procedure

Set the apparatus as shown in figure .

Take zinc granules in a flask.

Cork it properly but leave a side open for pouring acid

Drop wise pour acid into it say acid taken is dilute sulphuric acid  

Observation

The Reaction between zinc granules and  dilute sulphuric acid  starts .

Thta is : Chemical reaction : H₂SO₄+Zn--- ZnSO₄+H₂

Products obtained are :  zinc-sulphate and hydrogen gas  

Identification

The  beaker becomes hot  and hydrogen gas is produced which makes match stick burns with pale blue flame and popping sound