19,000+ solved questions for JEE Advanced, JEE Mains, NEET & IChO — with answers and expert explanations.
For the second period elements the correct increasing order of first ionization enthalpy is (NEET 2019)
Which of the following pairs contain metalloid elements in the periodic table? (Kerala CEE 2017)
The lUPAC name of an element with atomic number 119 is (NEET 2022)
Amongst the following, select the element having highest ionisation enthalpy. (MHT CET 2014)
The stability of +1 oxidation state among Al, Ga, In and TI increases in the sequence (AIPMT 2015)
Physical and chemical properties of elements are determined by
The electronic configuration of an element is 1s ,2s 2p ,3s 3p 3d ,4s 4p 4d ,5s 5p . From which group of the period table, it belongs ? (KCET 2012)
Identify the wrong statement in the following (AIPMT 2012)
The elements ‘X’, ‘Y’, and ‘Z’ form oxides which are acidic, basic, and amphoteric respectively. The correct order of their electronegativity is
Which one of the following arrangements represents the correct order of least negative to most negative electron gain enthalpy for C, Ca, Al, F and O? (NEET 2013)
Molybdenum metal is related to which block?
The hardest compound of boron is:
Which of the following is not true regarding the nature of halides of boron ?
In the structure of diborane
Boron nitride can be represented by the given structure. The structure of BN is similar to
Borax bead test is responded by:
An aqueous solution of boric acid is found to be weakly acidic in nature. This acidic character arises due to the following reasons.
When strongly heated, orthoboric acid leaves a residue of:
The bonds present in borazole are:
Which of the following is the electron deficient molecule ?
On the addition of mineral acid to an aqueous solution of borax, the following compound is formed:
Na B O .10H O X Y Z D D ¾¾® ¾¾® + X, Y and Z in the reaction are (a) X Na B O , Y NaBO , Z B O = = = (b) X Na B O , Y B O , Z H BO = = = (c) X B O , Y NaBO , Z B(OH) = = = (d) X NaBO , Y B O , Z B(OH) = = =
Borax is not used
In BX3, B – X distance is shorter than what is expected theoretically because (X = F, Cl, Br, I)
Na B O .10H O Na B O X NaBO B O Y z D ¾¾® ¯ D + 39. (S) Borax is used as a cleansing agent because on dissolv- ing in water, it gives: