List of top Questions asked in JEE Main- 2019

The correct statements among (a) to (b) are: (a) saline hydrides produce $H_2$ gas when reacted with ${H2O}$. (b) reaction of $LiAH_4$ with $BF_3$ leads to $B_2H_6$. (c) $PH_3$ and $CH_4$ are electron - rich and electronprecise hydrides, respectively. (d) HF and $CH_4$ are called as molecular hydrides.
The correct statements among I to III are : (I) Valence bond theory cannot explain the color exhibited by transition metal complexes. (II) Valence bond theory can predict quantitatively the magnetic properties of transtition metal complexes. (III) Valence bond theory cannot distinguish ligands as weak and strong field ones.
The correct structure of histidine in a strongly acidic solution (pH=2) is
The decreasing order of electrical conductivity of the following aqueous solutions is : 0.1 M Formic acid (A), 0.1 M Acetic acid (B) 0.1 M Benzoic acid (C)
The elastic limit of brass is $379\, MPa$. What should be the minimum diameter of a brass rod if it is to support a $400 \,N$ load without exceeding its elastic limit ?
The increasing order of nucleophilicity of the following nucleophiles is : (a) ${CH_3CO^{\ominus}_2}$ (b) ${H_2O} $ (c) ${CH_3SO^{\ominus}_3}$ (d) ${O^{\ominus}H}$
The integral $\int sec^{2/3} x cosec^{4/3}x\, dx$ is equal to (Hence $C$ is a constant of integration)
The IUPAC symbol for the element with atomic number $119$ would be :
The lanthanide ion that would show colour is-
The mean of five observations is $5$ and their variance is $9.20.$ If three of the given five observations are $1, 3$ and $8$, then a ratio of other two observations is :
The mole fraction of a solvent in aqueous solution of a solute is 0.8. The molality (in mol $kg^{-1}$) of the aqueous solution is
The noble gas that does NOT occur in the atmosphere is:
The number of 2 -centre- 2 -electron and 3-centre-2-electron bonds in $B _{2} H _{6}$, respectively, are :
The number of natural numbers less than $7,000$ which can be formed by using the digits $0,1,3,7,9$ (repitition of digits allowed) is equal to :
The ore that contains both iron and copper is:
The oxoacid of sulphur that does not contain bond between sulphur atoms is :
The percentage composition of carbon by mole in methane is :
The pH of a 0.02M $NH_4Cl$ solution will be [given $K_b(NH_4OH) = 10^{-5}$ and log2=0.301]
The $pH$ of rain water, is approximately :
The process with negative entropy change is :
The product formed in the reaction of cumene with $O_2$ followed by treatment with dil. $HCl$ are :
The ratio of number of atoms present in a simple cubic, body centered cubic and face centered cubic structure are, respectively :
The value of $\cot\left(\sum\limits^{19}_{n=1} \cot^{-1} \left(1+ \sum\limits^{n}_{p=1} 2p\right)\right) $ is :
The value of $\int\limits^{\pi/2}_{-\pi/2} \frac{dx}{\left[x\right]+\left[\sin x\right]+4} $ where [t] denotes the greatest integer less than or equal to t, is :
The Wheatstone bridge shown in Fig. here, gets balanced when the carbon resistor used as $R_1$ has the colour code ( Orange, Red, Brown). The resistors $R_2$ and $R_4$ are $80\Omega $ and $40 \Omega $ respectively. Assuming that the colour code for the carbon resistors gives their accurate values, the colour code for the carbon resistor, used as $R_3$, would be :