Chemistry Test Discussion | 2nd Year Test-2 | MDCAT Repeaters Test Series-1 |Session 2026|19-04-26

Ajouté : 2026-05-05

[00:00:00]Salam dear students, we are going to discuss the uh second year chemistry.

[00:00:07]Um The first question is uh about the alkyl halide. If you take tertiary butyl bromide and it is treated with alcoholic potassium hydroxide, so what will be the product? So, this is an example of elimination reaction or it is also called dehydrohalogenation.

[00:00:30]Because one hydrogen goes from here and one bromine goes from here. A carbon-carbon double bond is formed. The name of the product is two methylpropene.

[00:00:41]So, we get an alkene. Option number B is correct. Which one gives fastest hydrolysis?

[00:01:02]This is a weak bond.

[00:01:07]So, rate of hydrolysis or bond energy go ahead of the game.

[00:01:17]So, bond energy will this direction may be rather obvious. So, it is a stronger bond.

[00:01:24]Yeah, I was saying to hydrolyze hydrolyze me over. It is a weaker bond and it will undergo hydrolysis with ease.

[00:01:32]So, option number C is correct. Question number 84.

[00:01:37]Why HI rarely used industrially for alkyl iodide?

[00:02:00]Reducing agent here or it is also expensive.

[00:02:05]So, I'm told by I forgot they can do Grignard reagent can you be home and told by you take alkyl magnesium bromide.

[00:02:15]Order of reactivity of alcohol. Alcohol may I beg him to go and saw the alcohol was rather reactive or that ROH plus HX.

[00:02:28]This reaction may alcohol may carbon or oxygen bond to get there. By the reaction may OH bond to get there.

[00:02:36]So, the OH bond to get there to get the primary alcohol is more reactive. Like in job you bond to get there to get tertiary alcohol will be more reactive.

[00:02:45]So, option number B is correct.

[00:02:49]Question number 86. Grignard reagent react with carbon dioxide followed by hydrolysis.

[00:03:09]I take care of you all here and this bond to get there.

[00:03:12]So, you get CH3 CO negative and C double bond O and MgBr plus.

[00:03:22]And the second step is the home acid hydrolysis cut there. Acid is used as a catalyst.

[00:03:29]So, each part combined with the O negative. You get carboxylic acid that is acetic acid and you get this product.

[00:03:40]This is by-product, right?

[00:03:42]So, carboxylic acid is formed. Option number D is correct.

[00:03:48]Question number 87.

[00:03:51]Which compound will not react with Grignard reagent or water, carbon dioxide or ammonia? All of them react.

[00:03:58]Looking at Grignard alkane they can alkane are least reactive and they don't have active hydrogen.

[00:04:11]They do not react with the alkanes.

[00:04:18]Remember that among the organic compounds alkanes are the least reactive organic compounds.

[00:04:29]88.

[00:04:31]The product formed when methylmagnesium bromide react with formaldehyde.

[00:04:41]This is formaldehyde. This carbon is positive negative. This is negative.

[00:04:45]This is positive. So, this will combine here and this bond is broken down.

[00:04:52]O negative. This is an intermediate is formed.

[00:04:57]And in the next step it undergoes acid hydrolysis.

[00:05:03]So, we get this alcohol.

[00:05:09]This is [cough] primary alcohol and the name of this alcohol is ethanol which is also called spirit of wine. Spirit of wine is called that.

[00:05:23]And 95% ethanol 5% water.

[00:05:34]Rectified spirit get there.

[00:05:37]All the alcohol 100% pure or 100% ethanol then it is called absolute alcohol. You choose it. It's a really They are but I might say that ethanol when you are Christian number 88 may option number A is correct. Question number 89. Grignard reagent must be prepared in dry ether.

[00:06:05]Okay.

[00:06:06]Grignard reagent by Grignard reagent is used as a solvent.

[00:06:14]>> [clears throat] >> All is gone. Maximum here to get a mild pass to Grignard reagent by the RMGX.

[00:06:25]So, you do ether come on to get you all the time.

[00:06:30]Yeah.

[00:06:34]This Grignard reagent will stabilize Grignard.

[00:06:38]So, benzene I'm using it to get something you don't get all electron pair donor may be a ether electron pair donor and it stabilizes the Grignard reagent in solution. 90.

[00:06:53]Which reagent will destroy the Grignard reagent?

[00:07:00]Grignard reagent or I have this may be funny that to is key hydrolysis or you get H either I get there you bond to get there and plus MgX and OH.

[00:07:15]So, Grignard reagent you destroy or get there.

[00:07:19]Funny may you stable may you have it will convert into again. That's why for the preparation of Grignard reagent we don't use water solvent. We will be using inert solvent like dry ether which does not react with the Grignard reagent. So, option number C is correct.

[00:07:51]Question number 91.

[00:07:53]Number of moles of Grignard reagent to convert ester to tertiary alcohol.

[00:08:02]Making [clears throat] you made pass ester RC double bond O If you start home Grignard reagent may Grignard reagent This is for example Grignard reagent RMGX.

[00:08:18]And this Grignard reagent will combine in the first step.

[00:08:33]This is Grignard reagent RMGX.

[00:08:44]You will get RC double bond O R here R.

[00:08:51]In the first step one mole I'm Grignard reagent is key one mole to get that combined to get there. You will get ketone. You might have passed ketone there.

[00:09:05]If you start to get further I'm combined to get there another mole of Grignard reagent. You are there either I get there.

[00:09:15]You will get RC double bond O or you have R or you have or then you will get this intermediate.

[00:09:37]This is Grignard hydrolysis to get there.

[00:09:42]So, you will get R C O H and this is R and this is R.

[00:09:53]So, you get tertiary alcohol.

[00:09:57]So, in the first step, we combine one mole Grignard reagent, you will get ketone.

[00:10:03]And the second mole of Grignard reagent when combined with the uh intermediate form will produce tertiary alcohol.

[00:10:15]So, we require two moles of Grignard reagent to react with the esters.

[00:10:28]Esters Esters Grignard reagent two moles instead of one mole. But you get side aldehyde ketone one one mole combined with that.

[00:10:42]Question number 92.

[00:10:47]Which alcohol is most acidic?

[00:10:51]The other case substance of total alcohol there and there's more acidic or primary, secondary, or tertiary in primary alcohol is more acidic. So, KA of primary is greater than secondary than tertiary.

[00:11:06]But among all the alcohol, methyl alcohol is more acidic than ethyl alcohol.

[00:11:17]Question number 93.

[00:11:20]Lucas test Lucas reagent is a combination of zinc chloride and HCl.

[00:11:29]So, it's the side of the upper tertiary alcohol mainland tertiary all is called that the tertiary alcohol.

[00:11:37]So, white PPT is formed immediately.

[00:11:47]I got a cup of alcohol secondary alcohol head, then you get white PPT from 5 to 8 minutes.

[00:11:58]I got this side of primary alcohol head, the room temperature but it does not react.

[00:12:07]So, this is used to differentiate between primary, secondary, and tertiary alcohol. Option number A is correct.

[00:12:17]Question number 94.

[00:12:23]Which alcohol react faster with HCl and zinc? I got that alcohol with that again. Tertiary alcohol is the side immediately precipitated with that. The C option.

[00:12:36]Question number 90 uh question number 93, question number 94, question number 95.

[00:12:47]>> [clears throat] >> Dehydration of alcohol gives alkene.

[00:12:53][clears throat] Option number B is correct. Question number 96. Phenol is more [clears throat] acidic than alcohol.

[00:13:02]Why phenol is more acidic than alcohol?

[00:13:10]The SK value higher than here.

[00:13:14]I would do I would do that.

[00:13:16]The double bond phenol there hydrogen coordinate the head.

[00:13:22]It's a minus H positive in the car with that.

[00:13:25]So, you have a resonance phenomena with that.

[00:13:31]And this resonance phenomena makes this phenoxide ion more stable.

[00:13:40]So, the reason is resonance. So, 96 may option number >> [clears throat] >> the B is correct. Question number 97.

[00:14:01]Phenol react with sodium hydroxide to form sodium phenoxide.

[00:14:11]Sodium hydroxide I got that is the side reaction there.

[00:14:15]So, you will get water and sodium phenoxide.

[00:14:21]Option number B is correct.

[00:14:37]Question number 98.

[00:14:41]Which compound give white precipitated with bromine water?

[00:14:46]So, I got a phenol side bromine water mainland there.

[00:14:53]You get substituted product or the color is white white precipitated.

[00:15:02]1 2 3 4 5 6 2 4 6 tribromo phenol is formed.

[00:15:09]So, option number C is correct.

[00:15:13]Question number 99. Phenol gives violet color.

[00:15:19]Yeah, I might have a pass phenol head.

[00:15:22]I got a escape side FeCl3 mainland there.

[00:15:27]So, you will get the complex.

[00:15:33]It's the matter of SK value.

[00:15:36]Complex value.

[00:15:44]And this complex has white color.

[00:15:48]So, option number 99 may uh we have ferric chloride.

[00:15:57]Option number B is correct.

[00:16:04]Question number 100.

[00:16:10]The [clears throat] general formula for ether is This is very simple question.

[00:16:18]Option number B is correct. 101.

[00:16:22]Ethers are relatively unreactive because they lack the active hydrogen.

[00:16:32]The hydrogen carbon case that I get the or carbon or hydrogen the electronegativity may difference that I have no other.

[00:16:40]So, this is non reactive hydrogen. We can say it is less reactive hydrogen.

[00:16:48]It's the matter of those two acid or the hydrogen or the alcohol or the the water or the hydrogen so they are more reactive.

[00:16:58]The 101 may option number C is correct.

[00:17:01]102.

[00:17:03]Ethers are prepared by Williamson synthesis. You must have heard reaction there.

[00:17:08]Williamson synthesis this one again.

[00:17:12]It's the matter of that I get better alcohol case that sodium mainland there.

[00:17:19]So, you will get sodium alkoxide and hydrogen.

[00:17:26]I got you alkoxide ion there.

[00:17:29]It is a good nucleophile.

[00:17:34]It's the side of the alkyl halide mainland there. It is for a take care of that.

[00:17:40]And you will get ether in the product. The reaction is called Williamson synthesis.

[00:17:49]103.

[00:17:52]Ethers are diethyl ether react with hydrogen iodide.

[00:18:00]I got that diethyl ether mainland there.

[00:18:05]I got that side of hydrogen iodide mainland there.

[00:18:10]So, two moles of hydrogen iodide will combine with it.

[00:18:16]You will get water and you will get two moles of alkyl iodide.

[00:18:24]The 103 may option number C is correct.

[00:18:37]Question number 104.

[00:18:40]Which one is more acidic?

[00:18:43]So, you have the other case.

[00:18:47]Carboxylic acid, phenol, water, alcohol, alkyne, alkene, or alkane.

[00:19:06]You have the acidity order here. So, you have the other case.

[00:19:09]Uh option number C is my correct here.

[00:19:12]105.

[00:19:14]The order of boiling point alcohol may hydrogen bond with that and that's why that is the SK boiling point with that.

[00:19:21]Order uh ethers or ethers order has those kind of boiling point with that order.

[00:19:29]106.

[00:19:31]Which compound will not give hydrogen gas with sodium method?

[00:19:36]The alcohol or phenol with that side sodium case that reaction with that and because they have active hydrogen but it will not react. Option number D is correct.

[00:19:50]>> [cough] >> 107.

[00:19:54]which alcohol will not undergo oxidation?

[00:19:58]So, tertiary alcohol oxidation as soon as you say mainly what do you have?

[00:20:05]All is given that yeah, yeah.

[00:20:09]You have a local one water.

[00:20:11]So, it's just that hydrogen may not be as good as here as soon as you oxidize mainly over.

[00:20:18]108 Uh the compound this this is named is So, this is actually built to iron.

[00:20:31]Option number B is correct.

[00:20:34]This is built one and built one in.

[00:20:43]Yeah, one built in B is called up here second one built in our built one in.

[00:20:51]Question number 110 You do compound have CH3 CH2 CH CH3 CH CH3 or CH3.

[00:21:10]So, this is can be written in this form.

[00:21:14]1 2 3 4 and 5. This is pentane and 2 3 dimethyl.

[00:21:21]Option number A is correct. Question number 111.

[00:21:26]You think [clears throat] I got up tell me to start carbon tetrachloride solvent with chlorine Milan.

[00:21:38]You call I got catalyst now or the substitution reaction may over is the substitution we need iron chloride catalyst, right?

[00:21:48]All I got up Uh you have a problem Uh addition reaction got there to addition reaction as soon as you may have that because uh aromatic compounds are stable.

[00:22:02]So, this will not easily undergo chlorination reaction.

[00:22:08]Uh I got you have a problem of sunlight is the matter again. The only you have to go hydrogen place on here by halogen. Like until and unless you use bromine here, the reaction uh the catalyst to work here the reaction will not take place. So, there will be no reaction. 112 Which of the following is the most activating group? So, they call you know you know to our CN they are deactivating group our NH2 or you do so you go group here to you activating group and making NH2 and may substitute stronger here. I got benzene you can start of NH2 a case to you as soon as you have a local electron donated as you have that.

[00:22:56]Like I got you have a problem of is the matter you have a lot of group attached to you there.

[00:23:05]Oh, take it you have a local one pair there second like and you have a problem electron withdrawing group be attached to you electron copy check it up and it will attract you there.

[00:23:16]You have a negative inductive effect you have that.

[00:23:19]So, it's just that it's your electron donating ability have a local or that you have a local group you have that or you directly electron donate got there is the matter electron withdrawing group may have to you at the activator.

[00:23:33]Question number 112 man NH2 113 Which alkyl halide has highest reactivity? So, you do bond weaker over all highly reactive over alkyl iodide are more reactive.

[00:23:48]The CH bond has highest bond energy. So, fluoride bond energy you have that over here because carbon and fluorine bond is stronger ethyl chloride with nascent hydrogen nascent hydrogen got matter what that atomic hydrogen or I got up is the matter nascent hydrogen with iron.

[00:24:08]So, as hydrogen is the matter with iron or chlorine that CHCL so, you will get ethane. Option number B is correct.

[00:24:15]Question number 116 Which is not a nucleophile?

[00:24:20]Nucleophile but you have a negative charge over.

[00:24:23]You have a long pair over.

[00:24:25]Like and I got up CH3 plus got there So, you electrophile here but it cannot work as nucleophile because there is no lone pair with this iron.

[00:24:40]Question number 117 Ethanol is used for the following purpose. Ethanol can be used for preservation, okay? It is used for preparation of hundreds and thousands of medicine. You have to take it. All by the way is called ethanol and got you man be the latter and it can be used as a fuel. Also, option number D is correct. Question number 118 Ethers are isomers of alcohol. I have to put it over here dimethyl ether or you have a matter of ethyl.